Change pindexMostWork parameter of ActivateBestChainStep() to reference

diff --git a/src/validation.cpp b/src/validation.cpp
index d57997ce..3ed267b0 100644
--- a/src/validation.cpp
+++ b/src/validation.cpp
@@ -3172,18 +3172,18 @@ void Chainstate::PruneBlockIndexCandidates() {
 }
 
 /**
- * Try to make some progress towards making pindexMostWork the active block.
- * pblock is either nullptr or a pointer to a CBlock corresponding to pindexMostWork.
+ * Try to make some progress towards making index_most_work the active block.
+ * pblock is either nullptr or a pointer to a CBlock corresponding to index_most_work.
  *
  * @returns true unless a system error occurred
  */
-bool Chainstate::ActivateBestChainStep(BlockValidationState& state, CBlockIndex* pindexMostWork, const std::shared_ptr<const CBlock>& pblock, bool& fInvalidFound, std::vector<ConnectedBlock>& connected_blocks)
+bool Chainstate::ActivateBestChainStep(BlockValidationState& state, CBlockIndex& index_most_work, const std::shared_ptr<const CBlock>& pblock, bool& fInvalidFound, std::vector<ConnectedBlock>& connected_blocks)
 {
     AssertLockHeld(cs_main);
     if (m_mempool) AssertLockHeld(m_mempool->cs);
 
     const CBlockIndex* pindexOldTip = m_chain.Tip();
-    const CBlockIndex* pindexFork = pindexMostWork ? m_chain.FindFork(*pindexMostWork) : nullptr;
+    const CBlockIndex* pindexFork = m_chain.FindFork(index_most_work);
 
     // Disconnect active blocks which are no longer in the best chain.
     bool fBlocksDisconnected = false;
@@ -3207,13 +3207,13 @@ bool Chainstate::ActivateBestChainStep(BlockValidationState& state, CBlockIndex*
     std::vector<CBlockIndex*> vpindexToConnect;
     bool fContinue = true;
     int nHeight = pindexFork ? pindexFork->nHeight : -1;
-    while (fContinue && nHeight != pindexMostWork->nHeight) {
+    while (fContinue && nHeight != index_most_work.nHeight) {
         // Don't iterate the entire list of potential improvements toward the best tip, as we likely only need
         // a few blocks along the way.
-        int nTargetHeight = std::min(nHeight + 32, pindexMostWork->nHeight);
+        int nTargetHeight = std::min(nHeight + 32, index_most_work.nHeight);
         vpindexToConnect.clear();
         vpindexToConnect.reserve(nTargetHeight - nHeight);
-        CBlockIndex* pindexIter = pindexMostWork->GetAncestor(nTargetHeight);
+        CBlockIndex* pindexIter = index_most_work.GetAncestor(nTargetHeight);
         while (pindexIter && pindexIter->nHeight != nHeight) {
             vpindexToConnect.push_back(pindexIter);
             pindexIter = pindexIter->pprev;
@@ -3222,7 +3222,7 @@ bool Chainstate::ActivateBestChainStep(BlockValidationState& state, CBlockIndex*
 
         // Connect new blocks.
         for (CBlockIndex* pindexConnect : vpindexToConnect | std::views::reverse) {
-            if (!ConnectTip(state, pindexConnect, pindexConnect == pindexMostWork ? pblock : std::shared_ptr<const CBlock>(), connected_blocks, disconnectpool)) {
+            if (!ConnectTip(state, pindexConnect, pindexConnect == &index_most_work ? pblock : std::shared_ptr<const CBlock>(), connected_blocks, disconnectpool)) {
                 if (state.IsInvalid()) {
                     // The block violates a consensus rule.
                     if (state.GetResult() != BlockValidationResult::BLOCK_MUTATED) {
@@ -3372,7 +3372,7 @@ bool Chainstate::ActivateBestChain(BlockValidationState& state, std::shared_ptr<
                 // in case snapshot validation is completed during ActivateBestChainStep, the
                 // result of GetRole() changes from BACKGROUND to NORMAL.
                const ChainstateRole chainstate_role{this->GetRole()};
-                if (!ActivateBestChainStep(state, pindexMostWork, pblock && pblock->GetHash() == pindexMostWork->GetBlockHash() ? pblock : nullBlockPtr, fInvalidFound, connected_blocks)) {
+                if (!ActivateBestChainStep(state, *pindexMostWork, pblock && pblock->GetHash() == pindexMostWork->GetBlockHash() ? pblock : nullBlockPtr, fInvalidFound, connected_blocks)) {
                     // A system error occurred
                     return false;
                 }
diff --git a/src/validation.h b/src/validation.h
index cee0dd72..8816b070 100644
--- a/src/validation.h
+++ b/src/validation.h
@@ -851,7 +851,7 @@ public:
     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, std::vector<ConnectedBlock>& connected_blocks) EXCLUSIVE_LOCKS_REQUIRED(cs_main, m_mempool->cs);
+    bool ActivateBestChainStep(BlockValidationState& state, CBlockIndex& index_most_work, const std::shared_ptr<const CBlock>& pblock, bool& fInvalidFound, std::vector<ConnectedBlock>& connected_blocks) EXCLUSIVE_LOCKS_REQUIRED(cs_main, m_mempool->cs);
     bool ConnectTip(
         BlockValidationState& state,
         CBlockIndex* pindexNew,