OG Star Trek, Star Trek: TNG, DS9 and Voyager are the beating heart of Star Trek as far as shows. After that is Enterprise, Picard, Strange New World’s and Discovery for live action and Lower Decks and Prodigy for animated. I only have opinions on Enterprise and Prodigy. Enterprise completly skippable. Prodigy seems good but haven’t gotten through much of it yet.

For movies there are six movies that take place in the OG Star Trek era (I like all the originals personally but some are unliked by fans).

Then there are four movies in the Star Trek: TNG era but Insurrection and Nemesis, the last two, are generally not well liked, but views could have changed with time. (I enjoyed all these as well)

(All ten of the above Star Trek movies were my childhood and therefore have a lot of nostalgia for them. So my views are skewed.)

After that you have the reboot movies which are completely skippable (my recommendation). I watched the first one and was so nonplussed I never bothered with the others. Also, J.J. Abrams is involved in them so if you like what he does you may like the movies. Personally he’s on my shit list with M. Night and avoid any projects involving them.