i used this phone for a year. the phone is a bit bulky and heavy, but not much more than a flagship phone with a case on it. i never needed a case because of the metal build, and the back is this rubber/plastic material that's really nice. no stupid glass that will crack if u drop it.
the back comes off nice and easy and everything is removable with a screwdriver. the battery doesnt require a screwdriver to remove if i recall correctly. the replacement parts are available on fairphone's website. the bootloader is unlockable so you can change the OS if you wanted to aswell. the stock OS isn't so comfortable so i do recommend trying out alternatives, i had good experiences with /e/ and CalyxOS.
the fairphone marketing is a bit gross in my opinion. removing the headphone jack right as they release their own wireless accessories. having the hardware inside the phone for a second SIM, but making it inaccessible to end-users. promising 5 years of warranty and software support despite using old hardware that will not have 5 years of firmware updates, let alone security updates down the line. they base this on their long-term updates to fp2 and fp3 which also lack these critical components.
the phone's specs are nothing special. which is fine when you consider that the premium you're paying is for your own ethics; NOT the quality of the phone. but remember, fairphone are no stranger to misleading marketing and greenwashing. if you care about security updates, this isn't a 5 year phone as they're promising it to be.
i ended up installing grapheneOS on a used pixel, that's my phone now. it's a much, much better experience and i get to know that it will hold this quality of life for a long time to come. i do miss the removable battery, though.
please correct me if im wrong on anything.