I use cloud (Proton) as a backup only, in case SHTF. I'm curious, what do you use to synchronize your files, notes, and media across your phone, laptop, and tablet (if applicable)?

I'm using Syncthing, which runs locally and seems to be working well. In the past, I used Nextcloud for about two years but ended up switching because I found Syncthing to be a simpler and safer solution.