Is it OK to put a new TV over a mantle with gas logs in the fireplace?

All good, go for it!

I have a propane gas fireplace with a tv above. Our mantle deflects most of the heat and the tv is far enough away from the fire that it doesn't get warm at all. So I think it depends on the layout.

Your fireplace should be direct vented to the outside via a shielded duct. That protects your drywall and framing from fire and heat. Any heat that comes in to the TV area is likely just warm. However, some electronics are sensitive. Be sure the vents on the TV have adequate airflow

I have my TV over a wood burning fireplace for four years and have had no problems.

dont worry about it. the products of combustion are vented out. I had one put in at house no. 2 to keep the lower level warm. It was programmable to the temp you wanted. That’s about the only thing I miss about that place.

Consider if your neck will get tired. TV is supposed to be viewed at eye level. This will be anything but eye level.

We have one on ours with no problems!