I would recommend skipping TOS as a show, and reading the James Blish adaptations of it and TAS. They’re great stories, but getting various production design and execution issues out of the way is IMHO a good idea. Maybe watch some of the classic episodes like Shore Leave City on the edge of forever The trouble with tribbles
Then watch the original 6 movies - these are pretty good and varied. (except ST V, which… you can skip, or watch if you’re a completest or take as an alternate story, or whatever.) TMP is a little slow, and unique, but I think if you’re into general sci fi, and are ok with it not exactly feeling like “Star Trek”, it’s quite good and sets up Spock a little.
Then TNG, DS9 are both quite good, though DS9 really ends up being arcs of arcs for the last few seasons, so you can’t dip in and out the same way you can with TNG or TOS.
TNG Movies are with hindsight and time … ~~~ average? OK?
Generations is generally panned, I think it was basically another episode of the series with a bigger budget, and a middling one at that. First Contact is fun, but don’t think too hard. Insurrection is like Generations - I enjoyed it as it was, but it kind of re-made an existing TNG episode, and meh. Nemisis sets up the Picard show, but both are generally so bad that I can’t really recommend it.
Honestly, Voyager is flip a coin. I watched it once - first run on air, never have been interested in going back for a rewatch, and doesn’t really set up anything for future shows / makes some parts of future shows worse because of how much they screw up in the future shows.
Hot Take, Enterprise is worth watching, and I think air order works better here. Again, they can’t help themselves but “ruin” some earlier episodes / stories from TOS / TNG because of fan easter eggs or whatever, so - watching it later as it aired makes it so you get what they’re winking about. It also helps answer some lingering questions from other shows (if you care for that) in the 4th season. I will warn you, it’s probably a straight average 5/10 so there’s some lows, and very few highs - most episodes are … OK. Then again, if you can get through TOS and TNG lows, you’ll be fine here.
I think you can skip the 09 reboot series of movies, unless you really like JJ Abrams, lens flare, or some of the actors (or are a completest). Looking back, they’re entirely forgettable and not that great sci fi action films.
Looking back, I’d take a hard pass on Discovery and S1 and S2 of Picard, unless you like pain and screaming at the TV (assuming you actually liked TNG and 90s trek). S3 of Picard is OK, IF you’re super jonesing for more TNG no matter what. But really, TNG should have ended with All Good Things and left it there - that was a PERFECT ending, and they keep trying, and failing, to improve on it IMHO. So far, you can skip S3 of Picard and not have it affect anything else.
Lower Decks is surprisingly really really really good. Watch it.
Strange New Worlds is actually decent - and feels a lot like TOS in terms of episodic, random ups and downs in both good and embarrassingly bad episodes. It’s another prequel, but again, I think watching in air order makes sense - especially as it’s still airing new episodes, you can’t watch it first really.
I took a pass on Prodigy - opinions are mixed, and future availability and new seasons seem up in the air. It’s also a kids show from what I gather. I tried the first episode and was like - nah, not for me.
“Star Trek” homages - watch Galaxy Quest - that’s amazing. The Orville S1 and S2 are really good TNG. S3 changed and I did not like it as much, and dropped it part way through. They started being “extra serious” and like 1+ hour episodes and it just was a drag to watch for me.