I also suggest that you check into Hanon. No need to go through the whole thing, but I think it's No 39 or so that has besides scales arpeggios of Major, minor, diminished, dominant 7th and so forth. I was classically trained on the piano. The teacher made me practice every number in Hanon in four different ways. Pretty boring, but fortunately the scales and arpeggios were the most fun & practical part. I also suggest practicing on a 76 or 88 key not just for strethening but for running a wider range of arrpegios. When I picked up the accordion about 30 years ago, my fingers were too "strong" coming from a piano background and I was sloppy on the treble side. Two entirely different keyboard actions require different technics and approaches naturally. I feel a similar thing all the time when I go from my Korg Microkey 37 & 61 controller to the regular digital piano, but you mind quickly adjusts itself.