I have one of these! They are pretty cheap like 50-60 bucks. A couple companies make versions.
Anyways a few reason I dont love mine and havent really used it. It tends to peel up the edges of screen protectors when you put it on phones. Thats really annoying as they will never look right again. And you cant easily use it on a phone with a case, which is a must IMO. For all these reasons its best paired with a dedicated phone IMO. I have used some cheap but decent locked subdsidized phones as the main phone for it. Paid about $50 for these phones on sale. However without an OLED display that I've become so spoiled with those phones dont really cut it IMO. Still dont love it, to me it seems too wide or unwieldy (guess I wont like Switch or Steamdeck, which is likely accurate on both counts). Also in heavy play like heated streetfighter 2 its not as stable as a dedicated unit, it twists and creaks. Oh and support is spotty altho I think all emulators support it, I believe many native android games like COD mobile dont by design (they consider it cheating vs touch controls). Although fortnight is one biggie that does support it. I had a little china retro handheld called the Anbernic RG51 and found it much more natural and comfortable. But of course that was in a completely different league as not android based or phone-like at all.
However I guess in THEORY if you paired the Razer Kishi with a SD888 or SD 9 Gen 1 phone, you'd have some of the most powerful portable emulation possible. Even more than the below thing which uses a overclocked/air cooled SD845 (basically equivalent to SD 855)
But anyways they basically made a "phone as handheld" called AYN Odin and it's pretty much my most wanted toy, For some reason I want one more than a steam deck. Probably will order one soon (heavily backlogged)
You must really hate the Switch and Steam Deck then. Yes I know what you're gonna say LOL.