Unconfirmed txs in the GUI The GUI clumsily attempts to guess if unconfirmed txs are locked until a future time. This is currently based on the locktime only, not nSequence, thus wrong. Fix this by removing the clumsy code and treat all unconfirmed txs as unconfirmed. The GUI already prints whether a tx is in the mempool, in which case the user knows that the tx wasn't locked until a future time. If the tx is not in the mempool, it might be better to report the exact reject reason from the mempool instead of using incorrect heuristics. Confirmed txs in the wallet The wallet drops coins that it incorrectly assumes to be locked until a future time, even if they are already confirmed in the chain. This is because the wallet is using the wrong time (adjusted network time) instead of MTP, due to the -1 default argument of CheckFinalTx. The issues are fixed in separate commits and there is even a test.
Backport of core#24067.