You should consider opnsense instead of pfsense in any case.

If by app you mean container, no. You pull the latest image and rerun docker compose. It will make only the necessary changes, in this case restarting the container to update.

https://xkcd.com/1897/

For a generous definition of “original”.

Edit: very generous, since it’s just new text on the second panel in https://xkcd.com/1269/

Honestly, I don’t. The vast majority of my data is just stuff like Linux ISOs that I could download again. Important documents and stuff like that take up so little space that I just keep them in Google Drive. Most of my personal project work is on GitHub. And while neither of those are technically backups, it’s not a tragic loss if I accidentally delete everything.