Clearly there is divergence. Examples that I run into on a daily basis:

My credit union login does an infinite redirect on login. Works fine on Chrome (and all other major browsers)

Perplexity on the mobile version web search entirely broken. Loops with some error and becomes unresponsive. Works fine on safari.

Many other random stuff breaks at least a few times per day usually from login redirects and authentication. Extensions like 1Password have autofill only working some of the time. The list goes on