This happens on the latest version (0.4.3)

Ocean Monuments are too frequent (right next to each other)

Maybe it could be possible to decrease their spawn rate. I have attached a screenshot showing how frequent they are. And this is only one ocean, they are as frequent in all other oceans I have encountered.

This is vanilla behavior, as in Deep Oceans (Dark Blue), there is 1 ocean monument every dozen chunks or so. This wasn't as common back in 1.12, but it was upped in 1.16.

I've oddly only found one, despite a lot of hunting. RNG and all that.

Sometimes there's lots, sometimes none at all.