fix balance being stale cuz it's overriden by an old value

### cw_bitcoin/lib/electrum_balance.dart
@@ -36,6 +36,14 @@ class ElectrumBalance extends Balance {
   @override
   Money frozen;
 
+  ElectrumBalance copy() => ElectrumBalance(
+        confirmed: confirmed,
+        unconfirmed: unconfirmed,
+        frozen: frozen,
+        secondConfirmed: secondConfirmed,
+        secondUnconfirmed: secondUnconfirmed,
+      );
+
   static ElectrumBalance? fromJSON(String? jsonSource, Currency currency) {
     if (jsonSource == null) return null;
 

### cw_bitcoin/lib/electrum_wallet.dart
@@ -428,7 +428,7 @@ abstract class ElectrumWalletBase
       return;
     }
 
-    balance[currency] = newBalance;
+    balance[currency] = newBalance.copy();
   }
 
   Map<int, Set<String>> get addressesSetByAccount {
@@ -1845,8 +1845,8 @@ abstract class ElectrumWalletBase
           isViewOnly: false,
         )..addListener((transaction) async {
             transactionHistory.addOne(transaction);
-            await updateBalance();
             await updateAllUnspents();
+            await updateBalance();
           });
       }
 
@@ -1950,8 +1950,8 @@ abstract class ElectrumWalletBase
           unspentCoins
               .removeWhere((utxo) => estimatedTx.utxos.any((e) => e.utxo.txHash == utxo.hash));
 
-          await updateBalance();
           await updateAllUnspents();
+          await updateBalance();
         });
     } catch (e) {
       throw e;
@@ -2736,8 +2736,8 @@ abstract class ElectrumWalletBase
           }
         });
         transactionHistory.addOne(transaction);
-        await updateBalance();
         await updateAllUnspents();
+        await updateBalance();
       });
     } catch (e) {
       throw e;
@@ -4037,15 +4037,24 @@ abstract class ElectrumWalletBase
     var totalConfirmed = 0;
     var totalUnconfirmed = 0;
 
+    final confirmedByAccount = <int, int>{};
+    final unconfirmedByAccount = <int, int>{};
+    final frozenByAccount = <int, int>{};
+
     if (hasSilentPaymentsScanning) {
       // Add values from unspent coins that are not fetched by the address list
       // i.e. scanned silent payments
       transactionHistory.transactions.values.forEach((tx) {
         if (tx.unspents != null) {
           tx.unspents!.forEach((unspent) {
             if (unspent.bitcoinAddressRecord is BitcoinSilentPaymentAddressRecord) {
-              if (unspent.isFrozen) totalFrozen += unspent.value;
+              final account = unspent.bitcoinAddressRecord.accountIndex;
+              if (unspent.isFrozen) {
+                totalFrozen += unspent.value;
+                frozenByAccount[account] = (frozenByAccount[account] ?? 0) + unspent.value;
+              }
               totalConfirmed += unspent.value;
+              confirmedByAccount[account] = (confirmedByAccount[account] ?? 0) + unspent.value;
             }
           });
         }
@@ -4062,6 +4071,8 @@ abstract class ElectrumWalletBase
             element.value == info.value) {
           if (info.isFrozen) {
             totalFrozen += element.value;
+            final account = element.bitcoinAddressRecord.accountIndex;
+            frozenByAccount[account] = (frozenByAccount[account] ?? 0) + element.value;
           }
         }
       });
@@ -4089,13 +4100,37 @@ abstract class ElectrumWalletBase
       totalConfirmed += confirmed;
       totalUnconfirmed += unconfirmed;
 
+      final account = addressRecord.accountIndex;
+      confirmedByAccount[account] = (confirmedByAccount[account] ?? 0) + confirmed;
+      unconfirmedByAccount[account] = (unconfirmedByAccount[account] ?? 0) + unconfirmed;
+
       addressRecord.balance = confirmed + unconfirmed;
       if (confirmed > 0 || unconfirmed > 0) {
         addressRecord.setAsUsed();
         walletAddresses.clearLockIfMatches(addressRecord.type, addressRecord.address);
       }
     }
 
+    if (hasAccountsSupport) {
+      final perAccount = <int, ElectrumBalance>{};
+      final accounts = <int>{
+        ...confirmedByAccount.keys,
+        ...unconfirmedByAccount.keys,
+        ...frozenByAccount.keys,
+        ...walletAddresses.accountIndexes,
+      };
+
+      for (final account in accounts) {
+        perAccount[account] = ElectrumBalance(
+          confirmed: Money.fromInt(confirmedByAccount[account] ?? 0, currency),
+          unconfirmed: Money.fromInt(unconfirmedByAccount[account] ?? 0, currency),
+          frozen: Money.fromInt(frozenByAccount[account] ?? 0, currency),
+        );
+      }
+
+      accountBalances = ObservableMap<int, ElectrumBalance>.of(perAccount);
+    }
+
     return ElectrumBalance(
       confirmed: Money.fromInt(totalConfirmed, currency),
       unconfirmed: Money.fromInt(totalUnconfirmed, currency),
@@ -4138,13 +4173,19 @@ abstract class ElectrumWalletBase
     try {
       final fetchedTotal = await fetchBalances();
 
+      if (!electrumClient.isConnected || syncStatus is LostConnectionSyncStatus) {
+        printV("updateBalance: connection lost during fetch, keeping existing balance");
+        return;
+      }
+
       if (type == WalletType.bitcoin && hasAccountsSupport) {
         // If the wallet has accounts support, we only want to update the balance for the current account.
         final accountBalance = accountBalances[currentAccountIndex];
-        if (accountBalance == null) {
-          return;
+        if (accountBalance != null) {
+          balance[currency] = accountBalance.copy();
+        } else {
+          printV("updateBalance: no balance for account $currentAccountIndex, keeping existing");
         }
-        balance[currency] = accountBalance;
       } else {
         balance[currency] = fetchedTotal;
       }

### cw_bitcoin/lib/electrum_wallet_addresses.dart
@@ -1,3 +1,4 @@
+import 'dart:async' show Zone;
 import 'dart:io' show Platform;
 import 'dart:math';
 import "package:collection/collection.dart";
@@ -425,7 +426,7 @@ abstract class ElectrumWalletAddressesBase extends WalletAddresses with Store {
     updateAddressesByMatch();
     updateReceiveAddresses();
     updateChangeAddresses();
-    _validateAddresses();
+    await _validateAddresses();
     await updateAddressesInBox();
 
     if (currentReceiveAddressIndex >= receiveAddresses.length) {
@@ -506,7 +507,7 @@ abstract class ElectrumWalletAddressesBase extends WalletAddresses with Store {
       if (shouldSkipHardwareWalletType) continue;
 
       await _generateInitialAddresses(accountIndex: accountIndex, type: type);
-      
+
       // Legacy derivation for these types is identical to the standard one.
       if (includeLegacy && !LEGACY_DUPLICATE_ADDRESS_TYPES.contains(type)) {
         await _generateInitialAddresses(
@@ -1001,12 +1002,31 @@ abstract class ElectrumWalletAddressesBase extends WalletAddresses with Store {
     updateAddressesByMatch();
   }
 
-  void _validateAddresses() {
-    _addresses.forEach((element) async {
-      if (element.type == SegwitAddresType.mweb) {
-        // this would add a ton of startup lag for mweb addresses since we have 1000 of them
-        return;
+  static const _validationTimeSlice = Duration(milliseconds: 16);
+
+  Future<void> _validateAddresses() async {
+    final addresses = _addresses.toList();
+    final slice = Stopwatch()..start();
+
+    for (final element in addresses) {
+      try {
+        await _validateAddress(element);
+      } catch (e, s) {
+        Zone.current.handleUncaughtError(e, s);
+      }
+
+      if (slice.elapsed >= _validationTimeSlice) {
+        await Future<void>.delayed(Duration.zero);
+        slice.reset();
       }
+    }
+  }
+
+  Future<void> _validateAddress(BitcoinAddressRecord element) async {
+    if (element.type == SegwitAddresType.mweb) {
+      // this would add a ton of startup lag for mweb addresses since we have 1000 of them
+      return;
+    }
 
       try {
         final mainHd = _hdForAddressGeneration(