My biggest wins came a bit before joining this forum. Ditching Windows (using Debian) and hardening it with LUKS disk encryption and OpenSnitch against games that spy on me (FOSS usually does not spy). In the same move I got rid off Discord and using Matrix only, which I used for some years right now.
This week I got just a little, but also important improvement. I bought a new SSD and was setting up my old one as backup disk. While I used backups previously too, I created them manually. The new method is not just much more regular (set it up to 1x each day) and more robust, but is also an archive backup type. So I have a versioning of updates, which allows me to chose single files from a previous state. That is especially helpful on complex projects where a lot of file changes happen over time. From time to time I will also make a backup to an external device that keep a state when the whole PC becomes destroyed (fire etc). Who values disk encryption should also not forget to encrypt backup disks.
By all the danger from internet we should not forget such basic security things.