SD card handling in Android has always been… weird… due to Google being obstinate for over a decade. No reference device (Nexus/Pixel) had an SD card slot, so external storage was always something that kindasorta had support in the base OS but was always a poorly tested addon.
Basically the arguments for Google were:
- FAT doesn’t have an appropriate permissions model for Android
- We can’t use anything other than FAT due to compatibility reasons - even though the reality is that when someone installs an SD card in a phone it’s almost NEVER with the intention of ever moving it to another device for transfer
Eventually Google gave in and created adoptable storage to solve 1 and 2, but it’s always been an unreliable mess. If you DO use adoptable storage, it fuses in the external media so aggressively you have little to no control over whether stuff winds up on internal or external media. Have fun with weird-ass behavior if the SD card starts failing, especially since Google blocks access to dmesg unless you have a rooted device now, and that’s the only way to know your SD card is now throwing weirdo eMMC errors.
Android still sucks less than iOS, but it’s gone way downhill over the years in many ways.
Worse, you have a lowend Samsung-mangled Android phone. Samsung has a long history of breaking Android in strange ways. I haven’t touched them since the Superbrick fiasco. (Samsung produced devices with a known major defect in the eMMC firmware even after Google forced them to fix it in the Galaxy Nexus, and then patched around the issue with a hidden change to their recovery/formatting application since they could hide that in Apache-licensed code instead of GPL. When people in the FOSS community ran upstream Android, BOOM - the new Android 4.0 secure erase function had a small chance of causing permanent near-unrecoverable damage (not even JTAG houses could fix it) to the eMMC.)