EDS seems to be still the best bet - SD card ecryption - #4 by tcecyk
Adoptable storage is on its way out. I thought the key for FBE is also tied to the TEE, so not easily retrievable - this answer from 2019 says otherwise - https://android.stackexchange.com/questions/215491/cross-platform-compatible-encryption-of-sd-card-for-android/215896 never checked.
For LUKS you still need root or build AOSP yourself