>>714717147 (OP)Anbernic RG406H for 4:3 with serviceable performance with some of the harder to run games ranging from spotty to unplayable at around $170 (try PAL versions for more stable 50fps for some of them) or Retroid Pocket 5 for 16:9 for confident emulation across the board (maybe needing to stick to native resolution for a few of the really edge cases) for $220. Or Retroid Pocket Mini V2 for Pocket 5 level performance but a smaller with an almost-square screen for $200.
Either way, check out Youtube reviews, there's plenty of benchmarking and gameplay footage for all three of these.