Old timer here. It’s easy to be a completionist when you do it over decades.
Just watched them all as they came out for the most part, after starting somewhere mid season one of TOS. With the reruns, I was soon caught up.
But I always argue strongly that whatever show grabs someone most is the best place to start for them. There’s no ‘best’ way and some of the shows reach different demographics better or worse.
Our teenage kids have never made it through every episode of TOS or Enterprise, and balk at DS9. Each has watched every episode of at least one of the newer shows, but not the same ones. But they find different ones more interesting as they mature.