It's probably worth watching TNG before DS9. The contrast between TNG and DS9 with DS9's darker tone is an important part of the show. Probably the best episode in the whole series, "In The Pale Moonlight", is made all the better when you've seen what they're contrasting against.

Probably you should really watch TNG first, lots of characters and lore that would be needed to fully appreciate a lot of things that would otherwise fall flat at best or be outright not understandable. I don't think they matter to understanding the main arc but then the main arc is only a small part of the show.

(Voyager is entirely optional but a much welcome addition that happens concurrently at later seasons; I would recommend it on its own anyway.)

For all these shows, let them grow on you, the first season of each can be a bit awkward but then things start to fall into place, both in terms of characters/lore/setting/story/world building as well as actors themselves getting the hang of characters.

And yes there are absolute duds of episodes, but don't let that make you miss the absolutely fantastic ones.

Yes, you can watch DS9 without having seen the other series. I hope you enjoy DS9 and also the other series should you continue.

There are occasional TNG references but they are not important to the plot.

There are some characters from TNG who cross over into DS9, and one of the main characters in DS9 has a grudge against one of the characters in TNG due to events in TNG, whose effects offscreen relative to TNG are explored onscreen in DS9, for example. However, there are small flashbacks that act as explainers in DS9 for those who haven’t seen TNG, and the story focuses on the impact to DS9 characters and their motivations, so you might only have half of the story for those small details, but you’ll have the half that is relevant to the story that DS9 is trying to tell. You could easily watch the one or two TNG episodes involving Wolf 359 if you wanted to get the other side, though you could make do without, and come back to TNG after DS9 if you wanted afterward.

It’s hard for me to be entirely unbiased myself, as I watched the the original series (TOS) films without watching much of the OG series itself, and then watched TNG when it was airing, so I already had the context to watch DS9.

All of that is to say, I don’t think you necessarily need to watch TNG to appreciate DS9. The shows are mostly standalone and self contained. Also, I don’t think this is much of a spoiler, as the double episode premiere of DS9 pretty much includes all of what I’ve said above, in some form or fashion, with the exception of the introduction of some character crossovers of the TNG cast. I think it’s nice to know where those characters came from and what they went through prior to DS9, as the two shows were running concurrently, but neither show is written in such a way that you’ll feel lost if you don’t watch TNG first, though others may disagree.

You can start with DS9 and understand what's going on with the characters. Like many series it takes a couple of seasons to figure out what's going on and who the characters are, but in the end the payoff is fantastic. It was the first series produced after the death (and overall creative control) of Gene Roddenberry, which allowed it to step away from a utopian vision and address real issues in a complicated ugly universe.

For me DS9 is the best Star Trek series. It's hard to admit since I adore TNG but overall DS9 is better. A few characters in TNG become main characters in DS9. You don't necessarily need the history but it may seem odd watching DS9 and then TNG. As some of these DS9 characters play a much smaller part in TNG.

TNG introduced various civilisations that drive much of the plot in DS9.

Season 1: Ferengi

Season 4: Trill, Cardassians

Season 5: Bajorans

Also, Chief O'Brien and his wife Keiko who were recurring minor characters in TNG have more important roles in DS9.

I went on this journey with my son during COVID.

Watch a handful of classic trek to get the idea. Balance of Terror, city on the Edge of Forever, maybe Mirror Mirror or Trouble with Tribbles. They will seem very cliched.

Start TNG in the third season and just focus on the best episodes, the ones that are 8s or 9s on IMDB. Be sure to see The Best of Both Worlds I and I, the original season finale climax.

Skip a lot of the first season of DS9. Low IMDb will tell you which ones. But watch almost all of the later seasons.

Then play Star Trek Attack Wing!

Depends. I think it's worth starting with The Original Series because the older trek as aged just as well as DS9 if not even better and that way you get the whole context that people who watched these shows at the time did.

But all the star trek series are self contained enough that you don't really need to have seen the previous ones.

It's the best starting point in many ways!

You can but you'll miss important context.

TOS and TNG explain the Federation utopian universe, the ongoing conflicts and races, the moral dilemmas of the captains... I feel that starting with DS9 might get you miss the point a bit.

I would say to at least try to watch a curated selection of TNG episodes.

If you have the general idea about this universe you can just jump in and then watch other shows later. But mind that DS9 is a different kind of show when it comes to Star Trek. Personally, I find it much more appealing than the rest because of the core premise.

Babylon 5 explores some aspects deeply which were just glanced over in DS9 and that makes it an amazing show as well.