People talking about lag, the Kishi (and probably others of similar design) connects via USB C, connection is instant. No pairing. The split pad USB connection design is by far the best way to connect to mobile.
Seen a few recommend the SF30 Pro. I have one and have used it with an official 8Bitdo clip. Unless you are playing unattached, say with the phone sat on a desk, then regardless of lag I wouldn't advise for it. It's is massively imbalanced for any decent sized phone and becomes uncomfortable for a lengthy play session, not even lengthy in my case but ymmv.
Also any decent phone will smash the China handhelds at emulation. I'm playing Dreamcast and even a lot of Dolphin games at full speed on my S20 Ultra, they are playable on a ton of modern phones. Heck I'm even emulating shit like the Jag decently plus Ridge Racer Arcade etc via Mame .
I spent literally minutes setting up each emulator, once they're done they're done and the hardest thing you'll have to do is copy roms to a folder.
Add the Android native games then Xcloud and you have a brilliant powerhouse of a gaming device that deserves something like a Kishi.