I haven't used the FP4 personally so can't really comment on that, but a lot of the community who owned the 3 weren't too keen on the 4 the last time I was on their forums. Most of that was due to the software issues you mentioned, as well as the removal of the 3.5mm jack.

The improved GM1 isocell rear camera on the 3+ is pretty good for what it is, but on the software side there's practically no optimization there at all. In full manual with OpenCamera I can take better pictures than my iPhone 13 - lack of HDR (camera hardware supports it, no software implementation) and OIS aside. Others have used the Google Camera app on auto and they're very happy with what they get, I'm personally not too keen on the overprocessed look that some environments can exhibit though.

Ever since the leadership changes and designer departure following the 3+ release, a few mistakes have been made - unrepairable fairbuds being the worst one IMO!! Plastic sustainability of those buds aside, the three tiny unreplaceable batteries will be a one way ticket to the landfill once they're worn out.

Personally I'm hoping they develop a true successor to the FP3, really like the feel of this device