Dungeons and Dragons

Check out Lost Mine of Phandelver: https://www.dndbeyond.com/sources/lmop

It's a one-shot campaign, pretty much ready to go, to the point that I think it's even got pre-rolled characters included.

Very little set-up required beyond the DM familiarising themself with the campaign itself, and the players reviewing their chosen character and brushing up on the core rules of the game so that they know how to actually play.

Beyond that, pretty much everything else is already taken care of, so far as I know (I've never played it, but I know it's a firm favourite for beginners for these very reasons).

And as for DM experience, someone who is willing to put in the work kinda just has to bite the bullet and go for it. It's a skill like anything else, and you only get better through practice. Start with pre-written campaigns to help keep the amount of prep required and wildly unexpected events that require lots of improv on the DM's part to a minimum. Branch out from there into more homebrew stuff when you're feeling ready.

Above all though, just give it a shot and see what happens. There will always be reasons not to play, but if you've got a group who are willing to give it a go then you've already overcome the biggest hurdle by far.