Oven bakes unevenly, with top of baked goods overdone before cooked through. Suggestions?

I would try lowering the rack.

Another thing you might try is putting a baking stone (like a pizza stone) or even some bricks in the bottom of your oven. Also check: is your lower burner working?

Every time I move, I test the oven with a recipe I know inside and out. And that's my brownie recipe. I make it according to recipe the first time making sure the only thing that is different is the oven and check the brownie as it bakes. I can easily tell what's different about the new oven by how the brownies turn out because I know it so well.

An oven thermometer only works well if your oven isn't totally messed up like the one I have now. There's too many hot spots that even if the thermometer tells me one temp, it is not the same throughout the oven. Let's just say I had to develop brownie-baking maneuvers that involves rotating pan in diff directions, diff times, and adjusting temp during baking. :)

Good luck!

All of the above ... But also, are you pre-heating the oven fully. If not, the element on top will be on constant, burning your efforts.

Always listen to your oven and get to know it....never completely rely on what its telling you. Even recipes may not have a very efficient temperature. Once you understand your oven, you hold that power. If you notice things are baking unevenly, lower the temp so it has a chance to bake through before browning too much. Always check on your food well before the time is up and respond to what's happening. Until I can gauge what my oven is going to do, I check on things frequently. It may feel tedious, but it pays off. You can have someone recalibrate your oven, but that is unnecessary unless its a major issue. I would just keep moving things around until you find what works best. I've seen people test their oven with slices of white bread in a single layer on a sheet pan. You might try that.

Ideally, the first thing you should do is find an oven thermometer to see if the thermostat is anything close to accurate, before you put another item in the oven to bake. Many ovens have appallingly poor thermostats.

"Lower temperature? Move the rack lower? Only turn on the bottom element?"

All three of these are potential solutions, try each by itself and see which works best. Rather than cook (and potentially ruin) an entire batch of biscuits (or cookies), I would just try a couple with each method.

Also, there's the option of switch to the bottom burner only about halfway through the baking.

Good luck!