SD Card, LineageOS, having issues.

cross-posted from: https://reddthat.com/post/56970410

I just got a new device and flashed LineageOS to it. No issues there, that part is fine. What isn't fine is that I am trying to move music, videos, and pictures from my old device to the new one. Old device is stock Android, however hardware-wise the charging port / USB C port exploded a few years ago, so I can't plug it into anything to move things that way, and have to rely on either swapping SD cards back and forth or trying to use a nearby share service or cloud service. Problems: the cloud service I use is dogshit and the upload/download speeds are awful. Part of that is being stuck with the worst ISP and the other part is that it's not a great service and found out way too late. Not a viable option. The nearby share application I use is called LocalSend and it works fine, but I still seem to not have ALL the files I'm trying to move despite watching it move every single file. Lastly, when I have used the SD card swapping method, formatting it to different things, etc. I still have the issue of not all the files I want show up AT ALL. Example: trying to copy over roughly 14k to 27k songs, but each method I have used only produces approx. ~5k songs in total. What is going on here? I also have realized that I cannot write images in bulk to the SD card from the old device, as it stops and then gives me a warning about how it's been set to read only. The music when I transfer it this way does not give me the same message, but I still end up with a fraction of what I actually have. Is this an error mostly with the SD card and should I just buy a new one, or do you think there's something else going on here? I really want to move everything over and not have to just give up. I'll take whatever suggestions I can get. Only reason I think it could be an SD card issue is that when I tried to do backups of all data on both devices it fails each time. No specific errors other than just saying it fails.