Where do I make a cool launch video?

Well it depends on what you want to do in it really. I use Canva for a lot of the video work I do (for other things) - very simple to use, but you are limited in terms of editing capability. There are loads of free editing tools out there like DaVinci Resolve, Hitfilm Express etc. Screen recording is also super simple now too with things like Zoom, OBS (and I'm sure many others!)

I use a couple of tools, some paid and in some cases - I combine different videos manually in iMovie. - This place has some really cool video templates that you can work with, looks more professional than Canva https://www.renderforest.com/ however its not Free, but I find its worth the cost, I have made some really cool explainer videos from Renderforest - I tend to combine the output with videos I create from https://smartmockups.com/ .... you can get free templates here and instead of uploading an image, you upload a video or gif. If you combine the right mock-ups, you can make pretty amazing videos for free. If all fails, sometimes I just pay someone from Fiverr to do it, they can use proper video editing software like Adobe After Effects to create really cool effects, but you must get a good one - not all providers on Fiverr are equal, some are more equal than others :) Check out their example works first, and speak to the designer before placing an order.