will a pizza stone actually work inside an OTG?

It works, and it's arguably MORE valuable in an OTG than in a big oven - because weak bottom heat and poor thermal mass are exactly the OTG's known weaknesses, and a stone fixes both.

The rules: buy a stone (or better, a baking steel - conducts faster) sized to leave a little air gap around the edges. Preheat it properly - 30-40 minutes at max temperature, the stone needs to SOAK heat, not just feel warm. Launch the pizza directly onto it. The stored heat sears the base immediately instead of politely warming it... pale soft bottoms become blistered crisp ones.

Same stone transforms crusty breads in the OTG for the same reason. One accessory, two upgrades. The only mistake to avoid: cold stone into hot oven or wet stone into any oven - thermal shock cracks them. Preheat WITH the oven, always.