Every startup is unique and has its own requests - so it’s impossible to find a 100% suited video template. Additional editing is always needed. Also, many of your potential customers may notice if you use custom graphics or something that is being used by thousands of others. You can’t afford yourself a risk of losing any potential customers due to this reason.
So, if you can’t get a perfect video by yourself - it’s a question if buying a software subscription and paying for the template is worth it.