A poor man's Time Machine backup

Back in the day1 when I was still using a Mac, I always enjoyed the simplicity of Time Machine backups that Apple introduced almost 20 years ago. Simply plug in your dedicated drive, let Time Machine do its thing and hey presto, snapshots of your precious data. My wife’s MacBook Pro from 2013 is still backing up to a Drobo 5N of a similar vintage over SMB to this day. I tend to synchronise my important folders such as documents, photos and videos via Syncthing and that works without issue. However, I also have a large ~/Development folder that I don’t synchronise. To a degree this is due to the fact that I push most source code I care about to GitHub or Codeberg. I also had bad experiences with Dropbox in the past where its synchronisation mechanism would get confused with operations in the .git folder across multiple hosts. And because of that experience, I never used to back up my Development folder, which was a shame, really.