Files disappearing from directories on Micro SD cards / iPad Pro (2022 11.9) iPadOS 18.7.1 How to recover?

I am able to save videos off of FB and IG to my photo album and then export the unmodified originals to Files and an external Micro SD card before my iPad Pro (2022 11.9) iPadOS 18.7.1.. However files often disappear. It’s happened on a couple of my cards. The first time I had 1000+ loose files on the main drive folder and believed it was a file count limit and RAM deficiency problem so I organized them into smaller folders by topic.

I was able to run Disk First Aid App on that card (SanDisk UltraPlus 200gb) and I believed I recovered them all as I think they seemed to show up though it’s impossible to tell. I bought a new card (Ultra Team 1tb) thinking the previous card was defective, backed it up on my Mac and moved all the files on to the new Micro SD card.

On archiving and organizing a new batch of files tonight to that card I noticed that several previously archived videos were missing. I was able to do a search (keyword) and found them but on choosing the “show in enclosing folder option” in the pop-up dialog, none of the files would appear in the directory where they were supposed to be located. (Though did appear in search results directory.)

Even though I was unable to see the file in the folder I eventually was able to move them to a new folder but now believe I have many more files that have once again disappeared.

How can I recover these files so they stay revealed? Keep files from disappearing in the future? Is this a formatting problem of the SD card? A problem with the iPad OS? I don’t want to reformat the drive as a Fat 32 format. It is formatted in the original way it shipped which should be compatible with Mac OS journaling. As I have been archiving and organizing I have been truncating the file names under 40 characters and deleting any special emoji characters when saving. I can’t do a move and search as previously as I don’t know the names of the files that are missing (only those particular ones as I was actively searching). I know 30 years ago on the old Mac OS, SD card files would disappear if you did not routinely plug them in, but I use these regularly. Any advice please thanks.