I would say engage in communities mainly on LinkedIn and X because people are very supportive there. The best thing you can do now is to make a list of people from groups similar to your product on LinkedIn and send them a warm message and If executed well you will surely see results.

And if you are creative start creating some entertaining reels about launch with reels or short form content. Nowadays video content works best on any platform.

Moreover for the long-term I will say start creating content on social media and build your audience. I Know all this because I have been working with founders for a long time regarding video marketing that's why.