I'm in a suburb in Austin, I did chop out part of the lawn to plant a pollinator garden, but it's nothing really special. I made a project for my house, and I'm at 550 species total, 250 Lepidoptera (moths and butterflies). That's really just a result of regular observations. Every month I pick up at least a few new species. In the spring and fall I pick up a bunch, typically. Keeps adding up over time, and with moths there's a lot of species out there.

Is not really difficult to find this amount of biodiversity on most wild temperate gardens. With some effort you can easily have a collection of two thousand species of plants on a middle size garden if you want, plus animals attracted by those plants.

On tropical ones the number should be much, much higher.

Probably does, but if you pay close attention to the moths around your house over a year, I expect you'll exceed your estimates by an order of magnitude at least. They're incredibly diverse. (And many are super small, that you probably don't normally pay attention to or realize are moths.)

Only 10k more to go. There really are an obscene number of moth (and beetle) species.