Thankfully TOS never did any fantasy stuff like galactic barriers, Trelane, massive green hands in space, or Abraham Lincoln. That wouldn’t have been true to Gene’s vision.
I’m not a fan of Disco either, but tardigrades and time bugs are really low on my list of complaints. Star Trek did lots of even whackier stuff over the last 60 years (or did everyone forget the “Fun with DNA” episodes of the 90s?). In fact, that time bug episode was probably the best 32nd century Disco episode. Which is a low bar, but anyway.