What is a good practice regiment?
Like what should an ideal practice session look like?
Let’s say you have 1 1/2 hours to practice
How much should be dedicated to technique, whatever song you are learning and dynamics and the such?
If you are training for a sport, it's important to have a consistent regimen, so much time on sprinting, so much on endurance training, so much on weights. If you just devise it well and stick with it you will make progress. It's mostly muscles and cardio/respiratory fitness that you are building and all it takes is consistent effort.
I don't think piano is much like that at all. There is no ideal regimen that you can set up and carry out consistently and guarantee progress. Mostly you are training the brain, not building muscle, so it's very important to concentrate, and nothing kills concentration like doing the same things over and over in the same order - scales, arpeggios, sight reading, learning new pieces, polishing old ones, for so many minutes a day, in that order, for months or yeas at a stretch. It may be helpful to set up such a regimen and use it for a little while, but once it's become a routine, your brain will be more focused and you'll make more progress if you change it.
I'd say that you warm up a few minutes, if your body requires a warm up, and then do whatever you feel requires the greatest mental effort, whether that's learning a new piece, working out the voicing and phrasing for one where you know the notes but are not satisfied with how it sounds, memorizing a piece, figuring out why your f# harmonic minor scales feel awkward, whatever it is that's bugging and interesting you, and then move on to whatever is mentally a bit easier. Keep going till you run out of time.
Obviously the most mentally challenging thing will change week to week if not day to day, so you change your regimen as often as you need to. The main thing is not to think that you can make a great plan and then turn on the autopilot and get optimal results. You have to keep changing the regimen so that your brain stays alert.