Holy cow, yes. I switched to FF a while back, and your description of the behavior alone raised my blood pressure. They way return automatically opens whatever the first suggestion is immensely frustrating. The way hitting `return` is literally a race condition against how quickly the autocomplete returns its results.
There are some things I miss about Safari, but the search bar behavior is not one of them.
Wait until you see Spotlight in Big Sur beta 1, it teleports back in time to give you a result for the query you typed in the last time you opened it :/
There are some things I miss about Safari, but the search bar behavior is not one of them.