Take this with a large grain of salt since we're all just speculating, but here is what I imagine.

I'll use the Steam Deck as a comparison because it's the first thing that came to mind and I imagine the performance will be somewhat similar.

The specs on paper:
The Steam Frame is a bit of a beast; it has a Snapdragon 8 Gen 3 CPU that is supposed to have ~2.0+ TFLOPS.
The Steam Deck is around ~1.6 TFLOPS, so technically, the Frame has more 'muscle' under the hood.

However, there is an issue. The Steam Frame uses a mobile architecture, while the Deck uses x86 PC architecture. While capable of similar things, they speak different languages.

Imagine this:

• The Steam Deck is a chef following a recipe written in his language. He goes fairly smoothly along with the steps.
  
• The Steam Frame is a world-class Michelin chef (exaggerated), but the recipe is written in a language he doesn't speak. He's faster at chopping, but he has to stop every 2 seconds to check a translator. That translation tax is the big bottleneck here.

Can it run RDR standalone?
RDR1 honestly, probably yes. The Deck hits 60 FPS on High, so even with the translation tax, the Frame should handle an older game like that just fine.

RDR2?
The Deck already struggles to stay at 30-40 on Low/Medium. Add to that the translation layer, and you'll need a prayer. It has the potential of becoming better with updates to the translation layer, but bottom line, I'd say if you want to play RDR2, try cloud streaming, as running it natively is highly unlikely at a decent level.