There's a no background version of ffr but there's still animations on it and it's very laggy and unplayable, would be easier to try to memorize the patterns with the background already on.
If you're playing one handed or index switching to 4 fingers or spread should fix the jumps problems.
Try to play every songs in the game and FC them and try to AAA the easier ones unless you feel like playing hard songs then go for that.
Can't do much about Canon until decide to step the harder version and get it accepted.
The way to counter being anxious is to first play songs that are a bit harder than your comfort zone. Like, i'm currently playing FMOs and FGOs in order to come back to my Challenging and VC songs for the AAA.
FGOs need to be divided into many sections, like you mash what you cant do and do everything else and the more you're confident about your skills the more sections you do the normal way.
Sense of rhythm comes after playing a lot naturally and it's not eve

even a matter of skills, you just get it over time. Speed and bad habits are what you need to watch out for.
Wut? Ohai, i'm bored and felt like saying something.
Have a nice day.