I might be missing your point, can you elaborate? If you want to write an if statement you just do it at the end of a component, after the hooks. It's a common pattern.
Web libraries don't update more or less quickly than any other platform. The "issue" with web is the pace at which new frameworks are released but at this point even React is over ten years old. It's not that bad. Things are more stable than they used to be and new concepts are quickly adopted by each framework so you aren't forced to switch to something new, see for instance signals.