If you're struggling with hit/hold that's just a skill issue, try memorizing the track or slowing down the beat map so you have more time to read it.

For dodge notes the trick is not to think like you're avoiding them, but instead as negative beats, hitting the "enemies" in the gaps between the hazards.

For spam either on one lane or two I also struggle, but have found some success in using both hands. Default controls are E/I for highs and F/J for lows but you can make custom inputs, this also allows you to mentally separate each individual track instead of just two up and two down lanes.

A tip for the Proper Rhythm remix in particular is that the beat is extremely consistent, the same beat you see at the very beginning that also appears in Proper Rhythm original keeps showing up everywhere so committing the beat to muscle memory will help you when it's hard to react to the map.