This kind of infuriates me. On rare occasions loading into the game (unmodified) it’ll glitch out and forget to render the borders for a good 5 minutes or until first teleport. Like come on! I can see it! I know you’re doing it!
Another game, Code Vein (shut up, I love it, just embrace some trash from time to time) did the same thing. I could tell because the layering was messed up and your partner’s nameplate would render over the black borders by mistake …
Check out https://www.giuspen.net/cherrytree/, lightweight note-taking app with interesting scripting function built in.
Even if that’s not your cup of tea, it has the option to save your notebook to a single sqlite file, so I take that as good enough proof it’ll work for your similar purposes as well.