What?

You just start at Star Trek The Animated Series

If you like new stuff: Star Trek The Animated Series

If you like animation: Star Trek The Animated Series

If you enjoy older series: Star Trek The Animated Series

If you enjoy really old series: Star Trek The Animated Series

Yeah, I started with TNG a year or two ago. I’m now halfway through season 4 of Voyager, just from watching an episode every few days whenever I have time. Eventually I’ll move on to DS9, before digging into the movies (which I have simultaneously heard are incredible and hot garbage, depending on the individual user’s preferences) and the newer stuff.

I only very casually like Star Trek and have never been confused when watching any series from the first episode.* I don't know about all these fancy new Treks, but TOS, TNG, and DS9 were intentionally designed to be picked up during any random episode because that was how TV worked at the time. If you found a show during its fifth episode, you had no means of going back to the first four unless you happened to know someone who recorded them on VHS.

Lower Decks was also completely enjoyable to me even though my knowledge of the franchise is limited.

* I think it was Discovery we tried watching somewhat recently (not 100% sure on the title) where I was confused from the first episode, but it was in a "What the fuck are these creative choices?" and "Do people like this?" way.