Can I get my carefully thought-out previous settings back after HD crash?

You can move your metadata folder. There’s an option in the settings. I wouldn’t move it to a network location (like a NAS) because that would slow things down. A directly-attached USB drive would be fine, though.

That’s how to do it on Windows, but the procedure is the same (don’t worry about the external drive format; the MacOS default one is perfectly fine).