2022-23 (when he actually played significantly more minutes per game), they look like this:

Atiki 14.5 Minutes, 3.8 ppg 3.6 rpg, 1.1 bpg, 51.1 % FGs
Keita 16.1 Minutes, 8.3 ppg 5.4 rpg, 1.1 bpg, 61.0 % FGs

(Atiki did increase his FG % in 23-24 to 62%, but it was on a very low number of shots per game - 3. Both players could use improvement at the Free Throw line, as both are sub-60% FT shooters for their careers.

You can probably make an argument that some of the superiority of Keita's numbers is simply due to his being asked to do more at Utah due to their lack of other options, but the numbers seem to indicate that he is at least as good as Atiki, and you could reasonably say probably better, with the added benefit of having an additional year of development ahead of him. Could we find someone even better in the portal? Probably, as there are still roughly 1 million players available, but as a nearly guaranteed add, I think we could also do much much worse.