The total transaction count (for progress estimation) is counted as the known count at the last checkpoint, plus an estimated number per day.

The last checkpoint is now 996 days ago, and its estimated 60000 transactions per day leads to a total estimate of 96M transactions, while the real number is around 183M.

Fix this by updating the count, timestamp, and rate of transactions... with or without adding a new checkpoint.
static const unsigned int DEFAULT_LIMITFREERELAY = 0;
static const bool DEFAULT_RELAYPRIORITY = true;
static const int64_t DEFAULT_MAX_TIP_AGE = 24 * 60 * 60;
static const bool DEFAULT_PERMIT_BAREMULTISIG = true;
static const bool DEFAULT_CHECKPOINTS_ENABLED = true;
static const bool DEFAULT_TXINDEX = false;
static const unsigned int DEFAULT_BANSCORE_THRESHOLD = 100;
static const bool DEFAULT_ENABLE_REPLACEMENT = true;
static const bool DEFAULT_FEEFILTER = true;
static const unsigned int MAX_BLOCKS_TO_ANNOUNCE = 8;
static const int MAX_UNCONNECTING_HEADERS = 10;
static const bool DEFAULT_PEERBLOOMFILTERS = true;
struct BlockHasher
{
    size_t operator()(const uint256& hash) const { return hash.GetCheapHash(); }
};
extern CScript COINBASE_FLAGS;
extern CCriticalSection cs_main;
extern CTxMemPool mempool;
typedef boost::unordered_map<uint256, CBlockIndex*, BlockHasher> BlockMap;
extern BlockMap mapBlockIndex;
extern uint64_t nLastBlockTx;
extern uint64_t nLastBlockSize;
extern uint64_t nLastBlockWeight;
extern const std::string strMessageMagic;
extern CWaitableCriticalSection csBestBlock;
extern CConditionVariable cvBlockChange;
extern std::atomic_bool fImporting;
extern bool fReindex;
extern int nScriptCheckThreads;