[comex]

These days you can sideload apps with a free developer account (with certain restrictions), but it's meant for development - AFAIK using it as a general-purpose app distribution mechanism is a violation of Apple's ToS. But people do it anyway, and you could too.

Separately from the ban on third-party browsing engines, iOS has technical restrictions preventing you from mapping unsigned code as executable, so JITs don't work. There may be some ways around that if you have a developer signature, but its messy at minimum.