I think I might have come up with solution: virtual volumes. Before I had the chance to test it out, I found this: https://www.pasadena.edu/files/syllabi/lmjang_30369.pdf
It suggests making disk images of memory cards for storage/backup. That way you should be able to fool FCP’s L&T into thinking it’s accessing the same volume as before.
I’m testing this right now. My only fear is that it might be impossible to mount multiple cards at the same time. Right now I’m trying to take multiple old timelines online and each one has their own card.