@Vector1Turbo isnt a theme that comes up on shopify free or paid themes. Where did you get the theme from?
If its not an official shopify supported theme - you will have to contact the theme developer for help. Shopify does not offer support for themes created by third party developers.
That saying - usually video elements have an auto play option you can add to the code. Can you add a link to your site?
Try adding: muted playsinline
to your video attributes.
Here's a reference: