Can we reset TVHM after beating it?

I’m wondering if you can reset TVHM after you beat it. I haven’t done about half of the side missions but want to complete the playthrough to unlock mayhem, but I’d like to go back and do the side missions at some point.

Side missions don’t lock after completing the story. You can go back and finish them at any time post-story.

You can complete all side missions after beating main quest.
Also, yes you can reset TVHM. There’s a button prompt at mode select.