You absolutely can. You just have to pay Apple their $99/yr for the privilege. I have an app I vibecoded running on my phone to do regexps against a phone copy of /usr/share/dict/words because I find the regexp practice to be more fun when faced with a word game compared to getting stumped. There's some restrictions, like no running your own JIT on user specified JavaScript, aka no making a web browser, but for most apps I dare say you won't run into the limitations trying to scratch an itch.