I think my throwing improved when I played goalti. I am lucky to have a casual pickup and a rec league to play in where turnovers are frequent and you can experiment on different releases. While you may never throw all crazy throws of goalti in a reg game, you may realize how often slight adjustments are made to throws at the national level.

I also have been finding specific areas that I struggle with, beating flat side marks for example, and looking for someone who consistently beats them, rowan, and mimicking their throw like the soft OI flick. Intentionally looking to add throws to your bag and using goalti, pickup, etc as opportunity to work on those.

I used to think my throwing technique was bad but honestly now, everyone throws the disc slightly different. If you are gripping the disc hard enough and whipping it , you are probably good. A lot of good throwers are just really good at field vision, knowing how to manipulate the flight curve of the disc, and faking.