refactor: Simplify pruning functions

diff --git a/src/node/blockstorage.cpp b/src/node/blockstorage.cpp
index ec95f11b..41931a81 100644
--- a/src/node/blockstorage.cpp
+++ b/src/node/blockstorage.cpp
@@ -284,8 +284,7 @@ void BlockManager::PruneOneBlockFile(const int fileNumber)
 void BlockManager::FindFilesToPruneManual(
     std::set<int>& setFilesToPrune,
     int nManualPruneHeight,
-    const Chainstate& chain,
-    ChainstateManager& chainman)
+    const Chainstate& chain)
 {
     assert(IsPruneMode() && nManualPruneHeight > 0);
 
@@ -294,7 +293,7 @@ void BlockManager::FindFilesToPruneManual(
         return;
     }
 
-    const auto [min_block_to_prune, last_block_can_prune] = chainman.GetPruneRange(chain, nManualPruneHeight);
+    const auto [min_block_to_prune, last_block_can_prune] = chain.GetPruneRange(nManualPruneHeight);
 
     int count = 0;
     for (int fileNumber = 0; fileNumber < this->MaxBlockfileNum(); fileNumber++) {
@@ -337,7 +336,7 @@ void BlockManager::FindFilesToPrune(
         return;
     }
 
-    const auto [min_block_to_prune, last_block_can_prune] = chainman.GetPruneRange(chain, last_prune);
+    const auto [min_block_to_prune, last_block_can_prune] = chain.GetPruneRange(last_prune);
 
     uint64_t nCurrentUsage = CalculateCurrentUsage();
     // We don't check to prune until after we've allocated new space for files
diff --git a/src/node/blockstorage.h b/src/node/blockstorage.h
index 9ba7873c..70baa273 100644
--- a/src/node/blockstorage.h
+++ b/src/node/blockstorage.h
@@ -218,8 +218,7 @@ private:
     void FindFilesToPruneManual(
         std::set<int>& setFilesToPrune,
         int nManualPruneHeight,
-        const Chainstate& chain,
-        ChainstateManager& chainman);
+        const Chainstate& chain);
 
     /**
      * Prune block and undo files (blk???.dat and rev???.dat) so that the disk space used is less than a user-defined target.
diff --git a/src/validation.cpp b/src/validation.cpp
index 72872c5c..9ecfdfa1 100644
--- a/src/validation.cpp
+++ b/src/validation.cpp
@@ -2785,7 +2785,7 @@ bool Chainstate::FlushStateToDisk(
                 m_blockman.FindFilesToPruneManual(
                     setFilesToPrune,
                     std::min(last_prune, nManualPruneHeight),
-                    *this, m_chainman);
+                    *this);
             } else {
                 LOG_TIME_MILLIS_WITH_CATEGORY("find files to prune", BCLog::BENCH);
 
@@ -6399,22 +6399,22 @@ bool ChainstateManager::ValidatedSnapshotCleanup(Chainstate& validated_cs, Chain
     return true;
 }
 
-std::pair<int, int> ChainstateManager::GetPruneRange(const Chainstate& chainstate, int last_height_can_prune)
+std::pair<int, int> Chainstate::GetPruneRange(int last_height_can_prune) const
 {
-    if (chainstate.m_chain.Height() <= 0) {
+    if (m_chain.Height() <= 0) {
         return {0, 0};
     }
     int prune_start{0};
 
-    if (chainstate.m_from_snapshot_blockhash && chainstate.m_assumeutxo != Assumeutxo::VALIDATED) {
+    if (m_from_snapshot_blockhash && m_assumeutxo != Assumeutxo::VALIDATED) {
         // Only prune blocks _after_ the snapshot if this is a snapshot chain
         // that has not been fully validated yet. The earlier blocks need to be
         // kept to validate the snapshot
-        prune_start = Assert(chainstate.SnapshotBase())->nHeight + 1;
+        prune_start = Assert(SnapshotBase())->nHeight + 1;
     }
 
     int max_prune = std::max<int>(
-        0, chainstate.m_chain.Height() - static_cast<int>(MIN_BLOCKS_TO_KEEP));
+        0, m_chain.Height() - static_cast<int>(MIN_BLOCKS_TO_KEEP));
 
     // last block to prune is the lesser of (caller-specified height, MIN_BLOCKS_TO_KEEP from the tip)
     //
diff --git a/src/validation.h b/src/validation.h
index e14dac74..e810e872 100644
--- a/src/validation.h
+++ b/src/validation.h
@@ -835,6 +835,11 @@ public:
         return m_mempool ? &m_mempool->cs : nullptr;
     }
 
+    //! Return the [start, end] (inclusive) of block heights we can prune.
+    //!
+    //! start > end is possible, meaning no blocks can be pruned.
+    std::pair<int, int> GetPruneRange(int last_height_can_prune) const EXCLUSIVE_LOCKS_REQUIRED(::cs_main);
+
 protected:
     bool ActivateBestChainStep(BlockValidationState& state, CBlockIndex* pindexMostWork, const std::shared_ptr<const CBlock>& pblock, bool& fInvalidFound, ConnectTrace& connectTrace) EXCLUSIVE_LOCKS_REQUIRED(cs_main, m_mempool->cs);
     bool ConnectTip(
@@ -1325,12 +1330,6 @@ public:
     //! @sa node/chainstate:LoadChainstate()
     bool ValidatedSnapshotCleanup(Chainstate& validated_cs, Chainstate& unvalidated_cs) EXCLUSIVE_LOCKS_REQUIRED(::cs_main);
 
-    //! Return the [start, end] (inclusive) of block heights we can prune.
-    //!
-    //! start > end is possible, meaning no blocks can be pruned.
-    std::pair<int, int> GetPruneRange(
-        const Chainstate& chainstate, int last_height_can_prune) EXCLUSIVE_LOCKS_REQUIRED(::cs_main);
-
     //! Get range of historical blocks to download.
     std::optional<std::pair<const CBlockIndex*, const CBlockIndex*>> GetHistoricalBlockRange() const EXCLUSIVE_LOCKS_REQUIRED(::cs_main);