I have been searching for a single bit of Lapis but I can't find any. I don't know for sure but it seems that lapis does not generate in this snapshot. It is possible that it only generates without touching air, or the amount it generates is really small

Update: I did eventually find only 3 ores of lapis. But that is it so far
Update 2: Check pinned comment

Details:
Default world type and generation settings
Seed: 524848164558451417
The cave in question is around spawn with 2 openings. One being underwater and the second being in a nearby jungle. Let me know if you need exact coordinates.
There are no datapacks
This world is hosted on a server but it is a trusted host and should not change the world gen