I know that it is not particularly helpful to you but the camera loading time is crap on older models like XA2 as well.
See:
The lag started to be unacceptable when the Sailjail introduced (4.2 I think).
It is a shame that in 2022 it takes 10 secs to take a photo from the lock screen with a device which has as many resources what my desktop had 10 years ago…