Why does the right side of my 2020 MacBook Pro's keyboard get so hot?

There are a couple of things I would do, first if you haven’t sigh up for AppleCare+ so you have coverage longer than the standard warranty. I would also install a good thermal monitoring app like TG Pro. It also offers a turbo mode to increase the systems cooling fans which in turn should lower the keyboard temps.

One of the issues Apple has been facing is Intels inability to produce cooler running CPU’s. Don’t confuse the 10th Generation with the 10 um chips which are still MIA in this system which the system was designed for.

This is the root issue why Apple is jumping to their own silicon in next years systems.

Take a look through the 2018MacBook Pro 13インチ Touch Bar モデルの分解 which is structured the same as yours. Note the location of the CPU is and the heat pipes. Given the thinness of the system there just isn’t much space to isolate or insulate the keyboard from the heat from the logic board.