Hi and welcome. Moved your post here as the question was raised above, however I think not answered. As the forum is mainly a user forum, you might get a quicker answer when you contact Fairphone Support through their online chat
I do not know about the old or new Fairbuds, but with my Fairbuds XL using the V90 firmware (current version downloaded by the app), the presets/EQ setting persists, even if the Fairbuds XL are disconnected from Android, or are rebooted (powered-off then on again; I have no idea what happens if you remove the battery, or the battery drains). This is very convenient when switching between my FP3 and Linux laptop. So I presume you won’t have any problems, except if you to change the preset or EQ (then you must(?) use Android).
Update. The full review has been posted.
Tbh I am not competent enough to grasp most of the results.
I got interested in the review though when @schnitzel_vegan complimented their testing process.
I am not sure also I understand the issue with voice recording though.