From the square foot thing, I assume you’re in America?

That’s fine. I assume the router patches into a switch box, and the switch box patches into your room?

And what speed when you wire directly into the modem (bypassing the router)?

You don’t gain much putting an AP right at the edge of the footprint, eg where ‘mesh 2’ is in this diagram.

Arguably you don’t even need a mesh2. But if you’ve bought it and are going to use it anyway, I’d move to closer to the center. Or maybe next to the main computer, since that spot you will probably want to get the best signal you can?

Just wire your connection and you will get better pings, as well as not being affected by other people’s wifi use.

You won’t be taking all the bandwidth. Not even close. The problem is qos being enabled and your local wifi interference.