first time founder here, so take my advice lightly. from my research, the way to approach your launch is to find your ICP (ideal customer profile). after you know whom your target is, go to reddit and genuinely comment and solve their pain point, and lightly hint that you are currently working on a solution to solve that (sell your solution). this process takes way longer than ppc route, but it's effective. would love to see other's approach as well

Don't over-focus on one specific event in time like "launch", but instead launch it silently, purchase targeted ads or similar, share in relevant subreddits/reddit submissions (only where it's relevant) and ask the people who try it out for feedback. Basically, you want a small increase in users over days rather than huge increase of temporary users in few hours. Main point is to gather feedback early and be able to adjust quickly, without loosing momentum.

The whole "Launch Day" spectacle is over-hyped and only gets you low-engagement activity for a short period of time, while what you need to be looking for are users who like your value proposition, but they're getting stuck/thrown off somewhere, and you need to figure out where, before opening the flood gates.