How stagnated is Bitcoin development? Yeah it is not progressing super fast, but I think it is still progressing. Taproot has been accepted by miners and will be activated this year. Improvements are being done.
As Bitcoin is the biggest crypto by market gap, I think risk-aversiveness is a good thing. While I was initially a big blocker, now I think that going without a hard fork was probably quite a good idea. Bitcoin still works nicely and I still use it a lot, now I just use LN transactions in addition to onchain txes.