That's not how network effects work. Your complainers will go back to their subreddit and complain that your dating app is empty and all the profiles they're matched up with are 500km away.
The only way to have a fighting chance is to start in a single metropolis (eg New York), and try to get everyone to coordinate trying at once. Since the demographics of people complaining about dating sites online is a bit small (and selects for the kinds of clients you don't want), you've got to advertise more broadly, eg with ads on Youtube or in the metro. That gets expensive.
You don't actually need everyone to sign up at once. Once someone signs up you send them emails when they get a match. When there aren't as many people they don't get as many emails, but now they're on the site, which creates more matches for people who join tomorrow.
People need some way to find out about it, but not everything has to be corporate. Wikipedia has this page which ranks near the top for search queries like "list of online dating sites":
You're an online dating service, so you get added to pages like that where people end up when they're looking to choose an online dating service. And then your site compares well against the other ones that are screwing everyone -- look how few of the heterosexual dating apps have free messaging. So people sign up and give it a try.
You make sure your site is listed in places like that where people go to find dating sites, and people find it. And the more people find it, the more useful it gets, because that is how network effects work. At which point people start recommending it and you get even more users.
Another possibility is allowing people to sign up for waiting lists, and as soon as you have enough people in certain locations, you let them in. There's lots of possibilities of launching this correctly.
Sure, there's a lot of clever ways to get an audience as a dating site, and I've seen many sites with clever marketing tactics. The success rate is still abysmal.
The only way to have a fighting chance is to start in a single metropolis (eg New York), and try to get everyone to coordinate trying at once. Since the demographics of people complaining about dating sites online is a bit small (and selects for the kinds of clients you don't want), you've got to advertise more broadly, eg with ads on Youtube or in the metro. That gets expensive.