It’s interesting how differently repairs of unlocked devices seem to be handled in different European countries.
I think the main difference is that Switzerland has extremely strong and active consumer protection associations (on a similar level as Germany), so it’s not worth for company to piss off consumer.
Couple of years ago I sent my xperia x to repair in Finland because of broken back camera. They would have repaired it, but only after replacing the whole board because of the unlocked bootloader. the service company said that this was because of Sony warranty policy.
“Policies” of some private company cannot overrule European laws about warranty on consumer goods. That would be illegal.
Sony would have to prove that the unlocking of the bootloader caused the breaking of the camera. There is a very tiny sliver of truth here: on some older version of the Android firmware on Xperia X (I think up to Nougat ?) the Sony own special customized camera app needed the crypto key to unlock some special image processing custom code. So technically, on these old phones and firmware, unlocking the bootloader would immediately result in slightly degraded picture quality in the photos (on par of the other android phone with standard apps, instead of Sony’s custom app that should have Apple-level of photo touch-ups).
But that’s clearly not the case with you phone: the camera has been working successfully for quite some time on Sailfish until being completely fubar one day (not as in missing some processing bells and whistles but as in not working anymore), and as future proof, the replacement of the camera module and touching nothing else solved it perfectly.
In your case, I would try getting in touch with some local consumer protection association.
- If your phone was under warranty, they are obligated to repair the phone for free unless it’s the result of clear destruction from your action (it’s not, see above).
- If the phone is not under warraty, they still don’t have ground to force you to accept a full motherboard swap for some obscure “policy” reasons when that’s clearly not the problem (it’s probably a mixture of them wanting to be able to bill you a more expensive and thus more lucrative repair options, and of Sony probably wanting to keep their “intellectual property” protected by dissuading end-users to tinker with DRM and cryptokeys).
When not free under warranty, replacing the module your self is probably the cheaper option (though not easier given the glued together parts).