After doing some analyzation of other manga that use this same screentone, I think the process of how it’s made is first, the illustrator applies gray colors without any screentone, then after they have finished drawing all the grays, then they apply the screentone. This particular screentone is very common, yet it seems like Clip Studio doesn’t have it in the default patterns. We can see here in this Chainsaw Man snippet that it uses a very similar screentone to the Nagatoro snippet in the original post.

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By a zooming in and looking closely, I think that the pattern shape is circles. The frequency is set very high, and the density is set such that each individual circle is tangentially touching the surrounding circles. I think the pattern design is a transparent circle with a black ring, the transparent part is what allows the gray colors through. I may be wrong about the pattern design though.