Any way to limit FPS for multiple Roblox UWP instances?

I’m trying to run multiple Roblox clients and cap them all to like 10 FPS so they don’t fry my PC. RTSS is patched, FRTC doesn’t work, Radeon Chill only applies to one instance at a time.

Since Roblox killed multi-instance on the normal client, I’m using multiple Microsoft Store (UWP) installs, but UWP blocks most tools/overlays so nothing sticks.

Is there any way to globally limit FPS for all UWP instances, or make Radeon Chill apply to multiple Roblox windows or globally? Since it only allows one instance of roblox to be added and each time I add a new one it overrides.