I use my iPad for a lot of stuff, with StaffPad being the flagship app as far as CPU intensive. Even with art and drawing with ProCreate and massive note-taking and graphs and mechanical drawings, I barely use more than 150GB, even with a bunch of photos I've stored for editing. 512GB and the M1 to me IS future-proofing for quite a while to come. The 1TB and 2TB with 16GB of ram are needed tools for those who edit video using LumaFusion, ALL on the iPad. File transfer speed and local storage come into play. Christopher Lawley has a YouTube channel and does all video work exclusively on his iPad (plus he's one of the best if you REALLY want to know how to use all the iOS features). He needs lots of RAM and storage.
I truly believe that the M1 512GB iPad Pro is THE choice for us on here with StaffPad, Cubasis, etc. Dropping to 256GB to save some bucks is not a problem IMO. This is from a guy who has 48TB of drive space between my tower PC and external drives.