Honestly foam is way, WAY easier to work with than Pepakura, especially for beginners. It's also alot more apartment friendly (I know because I live in an apartment). A foam build can be done completely inside, the only time you're gonna need to be outside is when you plasti-dip & paint, you'll need space outside to work as you don't want to do that inside (trust me
). Foam is also cheaper & alot more forgiving than foam when (not if) you mess up.
As you've already learned, Pepakura can be VERY confusing. It's also WAY more time consuming & you use alot of different chemicals that are hazardous indoors (Resin, fiberglass, bondo, etc.). Helmets are usually better with the pepakura method, but if you don't have the space outside, it might be better for you to try to buy a premade, resin cast helmet.
Amazon sells foam & pretty much anything else you're going to need that you can't find locally.
Good luck with your build!