What phone are you using? If you’re using Android, the native APK version should perform much better. The HTML5 version on mobile may have some performance issues.
Yeah, to be honest, playing on iOS via itch.io is almost unplayable at the moment. It’s still technically playable, but there are hiccups and performance issues, so I wouldn’t recommend it on iOS for now. It seems to be an issue with iOS and itch.io themselves. Sorry for the inconvenience.