I started with TNG just because I've seen clips of Q. Worth it.
I have since finished TNG and am a couple episodes into TOS. Suprisingly TOS is not as bad as expected. It kinda holds up and the quality is pretty dang good on Netflix, again to my surprise.
Not sure I am gonna watch many of the other shows. I tried Discovery and Picard and I'm not really hooked. They are not bad, just eh. I do want to watch all the old movies though, right after I finish TOS which will probably take me a few years :D