What are good tips for an oven that is too hot at the bottom?
I'm a person that goes on vacation and bakes bread. As such, I have met a few terrible ovens around the world, and temporarily improved most of them to work better...

Grab a roll of aluminum foil (heavy duty is nice if you have it, or if you don't have any are are buying a roll with this in mind.)

On the bottom oven shelf, come in a few wires from the sidewalls (to allow some air circulation) and crimp on one end of a long sheet of foil - this sheet will be shiny side down, hung below the shelf, and attached to the shelf again in a similar location on the far side of the oven. You'll probably need two sheets (one for the front, one for the back) and should leave a similar small gap at front and back for some circulation, while keeping the centers tight or overlapped.

You can get much of the effect (but not quite as well, or as "semi=permanently") by putting foil, shiny-side down, on the bottom of your baking pans. If either is is not enough by itself, do both. It should help a lot.