Many of us feel the impulse to recommend whichever Trek first pulled us in. Others are completists or like to get everything in release or chronological order.
I see lots of recommendations starting along these lines here. That might not best for you OP. I’ve had the personal experience of watching everything in first run in release order, but I don’t know if I would attempt that if I were wanting to break back in after a long hiatus.
If you liked the original 1960s show (TOS) with Kirk, Spock and McCoy, Strange New Worlds may be your best entry point now. It takes place on the original Enterprise under an earlier captain, 10ish years before the time of the original show. Kirk and Spock are the same people you know but younger, and necessarily played by new actors. It’s designed to be a gateway show for fans who’ve never seen any Star Trek so you won’t be lost trying to figure out where things fit in. (The movies with Chris Pine as Kirk are set in a separate universe.)
If you were a Next Generation fan, then you might wish to start with Picard season three or Lower Decks.