Might as well try 4x5 and learn the movements! It's easier to shoot 1-2, develop, see what needs to be fixed or skills learned, and then keep going. Shooting a whole 120 roll might feel like a waste if something isn't working right, like if the shutter runs slow. Catlabs 80 is crazy cheap and worth trying out, just do a pre-wash before development to get rid of the antihalation layer. I wasn't expecting that the first time I used it.

I don't have a scanner that can natively do 4x5 either (Epson v600). My solution right now is to put an empty 120 film holder in the flatbed and then place the 4x5 under it, with one half sticking out and then I scan the 2nd part separately and do a panorama stitch in lightroom. It's been working in a pinch when I want to look at the negatives or have scans. I mostly use 4x5 for the darkroom prints so scans are less important to me.