Many company web sites feature some sort of video that plays in the background, covering the entire page. Some things to consider:
This is a background, and should not claim all the attention of the visitor. So pick calm videos, not highway car chases. Also, a series of 5 different short videos of lakes in New Zealand that loop every 10 seconds is still distracting.
A web site without content, but with a video in the background does not create a professional company presence. Content first.
Stock photos with model-turned happy diverse employees are boring, so are videos with the same people featuring in them.
If you have looked a web site (or presentation slide) for a long time as a designer you stop noticing things that a first time visitor will spot. Your brain knows the video loop by heart, filters it out, just to let you focus on that annoying DIV tag that refuses to line up. Force yourself to take that first time visitor perspective and ask yourself whether that video really adds something.
In the very early stages of a company, your website as actually aimed at investors. They want something that looks modest, professional, and with the essentials: a description what it is you are doing (consistent with the confidential pitch deck), a sense that you can communicate professionally and convincingly to future clients and investors, links to team bios, and hygiene factors such as a street address, proper domain name, etc. that shows that you are serious about your venture. Wild animations and spectacular videos do not always support this point.