The result is based on habit; the system learning your usage patterns - so long as you don't keep deleting History & Cookies. Every time you sweep your usage patterns, or use aggressive blocking tactics, ad blockers or VPNs etc, then the algorithms have to start again.
A "Top Hit" is somewhere you have been before, it's not the same as a Siri suggestion. Which lands at the top of the list is a simple algorithm - the one you either have been to most, or most recently if there's not enough habitual data to make a decision.
If you use one more than the other, it will swing the other way in a short while. I only need to type m
& Google maps is the autofill. I use Google Maps a lot; several times daily.
My partner has completely different usage patterns. She hardly, if ever looks at any map, so it's not 'habitual' at all. On her machine I have to type map
before anything map-like is suggested at all. There is no suggested auto-fill or top hit because I doubt she has ever visited any map site, ever. Apple maps at that point isn't even in the suggestion list