I also used to do SQL, as well as C++ (and many other languages) - doesn’t mean I’d use it for a webapp. Using the tools that best suit your needs is better than just using tools because you are comfortable with them.
You can also make non-relational databases have relationships, it just won’t be enforced/strict like it will be in a SQL database. For instance, making multiple matches relate to 1 video would be very simple by just having 2 match objects having the same videoId.
But yeah, that is why I’m asking you what the end game is, and this is the first time you’ve mentioned it will be as robust as it seems you’re making it out to be. If you’re looking to design around having many complex queries with multiple joints and stuff, then I wouldn’t recommend mongo. I’m always down to nerd out about development tools/architects.