I'm guessing since 18 had a kid that their bodies are pretty much purely human so Hit's assassination attacks should work on 17 without any issues. And that is the real problem. 17 might be on a even level with Hit as a fighter, but a Hit that can use all of his abilities should be able to kill 17 before there is even a real fight.
17 should be noticeably stronger than hit his feats this episode put him above most everyone we saw previously. His blast was probably the most damage we've seen jiren acknowledge. No idea who's win between these two both have the most op hacks and 17 has shown to be very proficient himself. Definitely would rather see hit fight him than rematch goku or vegeta
Goku only beat Hit's temporal abilities because they've fought multiple times, and Goku is *the* quintessential fighting prodigy.
Dyspo momentarily beat Hit's time-skip, because of his FTL fighting speed. Hit beat him to a pulp soon thereafter, though.
Jiren beat Hit's time-cage, because he's Jiren -- and that's back when they were hyping the shit out of him, to boot.
Powerful as he is, #17 still possesses none of the above haxx that might be indicative of beating Hit's temporal abilities. If Hit takes this seriously from the start, he *should* be able to win without too much of an issue, imo... Especially if killing techniques are allowed.