What is so bad about the repairability of the Jolla Phone? You can have a look at the teardown on ifixit. Seems pretty straight forward and modular. Sure, Fairphone is yet better, not so much because it is so much easier to take apart but because of how extensive their replacement part store is.

Not necessarily for Smartphones and Tablets. There is an exception:

manufacturers, importers or authorised representatives may provide the battery or batteries referred to in point (i)(a) only to professional repairers if manufacturers, importers or authorised representatives ensure that the following requirements are met:

(a) after 500 full charge cycles the battery has, in a fully charged state, a remaining capacity of at least 83 % of the rated capacity;

(b) the battery endurance in cycles achieves a minimum of 1 000 full charge cycles and after 1 000 full charge cycles the battery has, in a fully charged state, a remaining capacity of at least 80 % of the rated capacity;

See: https://eur-lex.europa.eu/legal-content/EN/TXT/HTML/?uri=CELEX%3A32023R1670

So If this requirements are met it does not need to be easily replacable by the End-User. Don't know If they can achieve that.