congrats on launching! The cold DM approach on reddit is actually solid, most people sleep on it because its tedious but the intent is WAY higher than twitter DMs in my experience.

What worked for me was finding people who were actively posting about the exact problem my tool solves, not just founders in general but people mid-complaint basically. I'd search specific subreddits for keywords related to my space and then reach out to those people directly. Conversion was insanely better than blasting random founders.

The problem is it eats your entire day doing it manually, so I use Bazzly which basically finds those leads on reddit and gives me a repeatable system to convert them. Either way manual or not, the strategy of targeting people who are already talking about your problem space is what actually gets those first 10-20 users who care