Can definitely confirm that there are several very playable avenue on Retroid Pocket 5: Android, Windows Bedrock via Winlator, Linux via Portmaster, the Switch version via Yuzu, the 3DS version via Lime3DS. I have not tested the Vita version via Vita3K or the PS3 version on Rocknix yet.
Had to guess, there’s some missing dependencies in Knulli that are present in MuOS.