Tumbleweed occasionally breaks something, but but it uses snapper to create a snapshot before each update, so if there's a problem, I boot into the most recent stable snapshot and wait for a couple of days before I update again.

Leap is very stable in my experience, while also offering relatively up-to-date packages.

The main problem is that out of the box, support for multimedia is not very good, but there is community-run repository with everything I need, i.e. video codecs and such.

If you have a spare computer, I suggest just installing it on that and giving it a try. Otherwise, a virtual machine. It's a lot more heavyweight than Slackware, obviously, and if you dislike systemd, you might not like it very much. But I don't know your preferences and requirements are, so the best I can say is to give it a try and decide for yourself.