This is contributing to thread-drift, I know, and it’s a well worn topic. But fwiw, when it comes to strap changes and avoiding scratched lugs, a bit of practice and a lot of patience can make all the difference.
As crazy as this sounds, before attempting to do anything on one of my nice watches, I’ll do a few trial runs on one of my cheapo pieces. Just to get a feel for it, as it’s not something I do very often. Also, I like using the Bergeron tweezer-style tool and follow the YouTube-guru guidance to pull the watch case away from the bracelet/strap, rather than pulling the bracelet/strap/tweezer away from the watch. The idea is that your tweezing hand stays fixed in place, and that decreases the risk of scratching the watch. Anyway, it works for me. I’m sure others have other thoughts.
I rarely bother with masking tape or anything like that.
I also don’t care that much if the underside of my lugs get a little scratched.