It appears to have that mode they call "Body Anchor" - limits the device to 72Hz with "minimal latency".

https://www.xreal.com/air2/

Thank you @hobos_delight! (Delightful information for me, 72Hz works for my system just fine thankfully.)

That's only with the XReal Beam. I don't know if it's possible to use the Beam and an external device like the Steam Deck together though.

Edit: yes, it appears it has a passthrough for displaying an external device - it does introduce a little latency though.