JS errors, page size, HTML errors, bad web design, CSS problems, SSL and broken layout has nothing to do with organic results or SEO and it is not proved that it affects your organic result position.
Even if it does, in-page problems doesn't affect your result not even by 1%. 99% is backlinks and their quality (or course).
Example: check techcrunch.com and debug/inspect their homepage. 15 JS errors, 6mb in size, no Description/Keywords, awful <title>, bad HTML elements. Can you even remotely beat them in the keyword "startup news"? No way. No matter how hard you will try to "SEO" your website.
I will tell it again. "SEO" was always a gimmick marketing thing. It's crazy that even now ppl don't understand that the only thing that matters are quality backlinks, as a result of quality content.