@dokkotak You're right, nice catch. I confirmed the same thing in mine.
And there is more. I don't have 22 rows in the Latest Updates tab in my front page. I have 21. And when I blocked DB to test, it fell to 17. Assuming you didn't count wrong (and perhaps you did, since you used ~ to indicate approximation), this means blocks affect the number of series in your front page.
Perhaps MDex is coded to list a maximal number of series in the front page (for people who block nothing), but not a minimal (or maybe there is a minimal but neither you nor I have reached yet). I know that this doesn't apply to genre blocks. I tried blocking isekai and the number of rows remained the same, and series had been knocked off the front page scrolled up back into it at the end.
Personally, I think if this is true, massive blocks will affect the usefulness of the front page, especially if someone blocks MangaPlus as you said. I think it would be better,
@Holo, if it's not a big deal in terms of coding, to make the group block conservative like the genre block is in terms of rows in the front page.
(Especially because if the much-awaited, future language of origin block comes in the same fashion as the group block, anyone who blocks isekai and manhua will be left with a very small front page.)