I've been seeing these little bugs in both of my bathubs, and my understanding is that the bugs are springtails, and they may indicate a moisture issue such as a drain leak. Does anything look off with these tub drains?

Not a plumber but look like my drains in this 80s house, which also attracts these thirsty bugs + gnats, mosquitoes, et al. once they breach my old exterior door seals or sneak in when door opened.

So I'm betting "the leak" is an avenue outdoor bugs find in your building envelop somewhere ... or the occasional open door ... they dry out, get thirsty.