Turn on streamer mode, and there is a setting to allow you to use mouse to control the offset. LMB = early and RMB = late. ofc this only works if you play with mouse, so idk about tablet players, My thought would be to remap your pen buttons or something. This works even if you have disabled mouse buttons during gameplay (in fact, you should do this). This will allow you to press any other two keys to the beat.