Fire Red .cia doesn't remember my saves after closing the game
UPDATE: I ended up trying a different .cia file and that worked normally, so the original problem was probably just the file being bugged. I followed the instructions linked in the comments to add the game on PKSM and now all is well.
I converted a Fire Red .gba file into .cia using vcoven and installed it through FBI. It's running with no errors and no lag, but if I save the game, close it, and then open it again, it starts from scratch without giving the chance to load the previous save.
For reference, I got my 3ds xl already modded but with an ancient version of luma/gm9, I looked into it to get familiar with how the modding works and I've updated both to the latest version (mentioning it in case it can be caused by me not updating them properly).
I had tried previously to run it as a .gba through mGBA but my 3ds xl is an older model and the lag was genuinely unbearable.
I tried to look for info here and on other platforms but most info on save files I've found were about importing them from a different source and not about the saves within the already installed .cia game itself.
I have also tried to run PKSM but since FR saves are not working there's no way for me to import it into the save manager, so I was just wondering if there was a way to get the game to save somehow (or if the problem is caused by me getting something wrong when I updated my console).
TL;DR Fire Red .gba converted into .cia runs normally but doesn't "remember" saves after closing the game. Is it user error or what is the best way to get the game to save properly?