Well if you want overclocking then a Z-series chipset board is basically the way to go.
In terms of itx boards, i’m still looking into the quality of the new upcomming Z390 boards.
Till now i only had the time to take a peak at the Asrock Z390 Phantom gaming itx,
and sofar it looks like a pretty sollid board to me,
That would be totally fine for overclocking the new upcomming i5’s or i7’s.
The board has a pretty decent vrm for that.
But for the topend 8C / 16T 9th gen intel chip, the vrm might be pushed a littlebit on this particular board.
I didnt had the chance to look at the Asus Z390 strix and the Gigabyte Z390 itx board yet.
But i will add that info to my Z390 vrm topic soon.
So you could keep an eye on that eventually if you like.