I was steered off after reading/watching lots of reviews of the Fairbuds reporting their audio quality is very average to low.

Seeking a battery-replaceable model I ended up going with the Samsung Buds Core which have a very similar Varta button battery to the Fairbuds. It is not designed to be user-replaceable, but isn’t very hard either - look up some YouTube videos and see if you’d be comfortable with the replacement process (its a bit fiddly).

P. S. As this is a Fairphone comm let me know if my comment is unwelcome. I love what Fairphone does and was keen to get their headphones, but couldn’t justify the cost with the performance. Hopefully the next version improves performance.