I’ve already used several Bluetooth headsets of serval brands with SailfishOS. All worked as expected. Also, interactions with buttons worked more or less. Remote control of audio player via MPRIS worked, however not all buttons operated as described by the manufacture, such as skip/jump to next track may be replaced by jump forward by 10 secs or 1 minute. Not sure whether this is an issue of MPRIS or the app that receive those MPRIS commands.
Play / Pause always worked for me, Volume up/down as well.
Picking up, rejecting or terminating a phone call hardly worked for me.
Other functions such as equalizer had to be done through companion app (on desktop).
Actually from Amazon’s product description and the manual, I don’t see anything crucial that requires the companion app. From my experience with my current Bt headset, tapping a button three times requires quite a bit of concentration and the error rate is rather high.
Maybe you can reprogram touch interaction with a desktop app.
If you go for those ear buds, please let me know if they keep the promise of noise-canceling and what you think about them. If you like them, I may swich as well.