At minimum, I rely only on these software that runs on all major platforms 1 :
- A web browser with adblock (eg: Brave, Safari)
- Syncthing (file sync)
- Pass with GPG (encrypted secrets & passwords)
Everything else is optional. This allows me to use any OS as I see fit, as well move between them as the situation requires, without developing dependency on one. Hence, “minimal base” of software use/dependency.