Transfers are usually pretty quick these days. Sometimes I transfer money from Schwab to Fidelity at night, and it's already available the next morning.
In the USA, a lot of the larger banks and brokerages (and maybe credit unions?) internally use systems like FedNow or RTP, which allow for instant transfers to other banks. It can take a little while if they do extra security checks though.
I've got a PowerCore 20000k (20Ah). I wonder why the 10Ah version is "fire-prone" but the 20Ah version isn't.