on my 15v4, the larger keys like lshift, space, and enter have a slightly different/louder sound than the smaller keys, but nothing that would make me think something is wrong.
you’ll have to be more specific on the password screen. If you have disk encryption in use, then you’ll get a LUKS prompt to decrypt the disk before the user login - that’s normal/expected.
there does appear to be ~1s of screen garbage when switching to/from 4K display resolution, not sure if that’s on the firmware or kernel driver side - I suspect the latter