I tried using LineageOS with an SD card as adoptive storage but ran into all kinds of quirks as well, described in this post and below:
https://forum.fairphone.com/t/lineageos-fork-including-microg/34877/94
I could not make it work and in the end stopped using adoptive storage. My SD is doing fine as regular external storage for videos etc.
Interestingly, I’m also using a 64 GB Samsung EVO.
Did anyone have issues with internal storage using another type of SD?