How to address error "Did not load script at 'script name' because non script MIME types are not allowed when 'X-Content-Type: nosniff' is given

I want to just delete the question but I hope maybe this answer will still be helpful to someone.

So, my problem was actually that I had a bad clone of my project and it was missing files!

However, for anyone having the same issue:

ensuring that type="text/css" for stylesheets and type="text/javascript" did fix the issue. (for the files that actually existed)