File System Recommendation for Micro SD Cards in fixed installation

To expand capacity in my small form factor desktop, I put a Mini PCI-E to Micro SD adapter into the motherboard’s empty Mini PCI-E (Wifi) slot (I am using a wired connection instead). There’s two 128GB Micro SD Cards (leftover from phone upgrades) installed, and UM recognizes both as “Generic Micro SD/M2 (1.08)”

There are no OS files on these disks. They are for non-essential storage, mostly downloaded television shows.

Since I won’t be unmounting/removing these SD cards, I don’t think I need to be tied to a “Removable Friendly” file system (FAT32, exFAT, etc.) and was wondering if there was a better option for this use case?

The other disks are SSDs with GPT partitions formatted in EXT4. I don’t know enough about file systems though, to know if EXT4 is a good idea for an SD Card (I assume journaling off, NOATIME, etc.?), or if mixing file systems would create headaches, for example if I used F2FS for them.

Thoughts or recommendations greatly appreciated!

Hi: I’ve been using a Micro SD card formatted primary ext4 and have had no issues. I have an hp stream 11 that only came with 32gb so have mounted a 64gb for elbow room. Seems to be a reasonable solution.

According to what I’ve read f2fs seems best for sd cards. But ext4 comes in second.
in any event let us know what you go with and how it works out for you.