In my honest opinion, doing seo without content is not gonna bring you the best results. You need content for each and every part of your process - meta tags, headings, website content, blog, links, social media etc. So always think about content before you begin seo process.
I think is 80% content and 20 % SEO. Even less SEO can make things work, but less content not so much. Content is everything. You have to think it this way: what do you bring to the table? What your website give to the visitors? For what reason will they come back ?
Content is a part of SEO. In the past, you could build a bunch of links and rank well, but today, is a bit different. Remember what happened to Amazon? They got hit for thin content. An SEO's job today requires you to do a lot more.
Contents make your website searchable in SERPs. If you don't need any organic traffic the you can omit this like for just a video/picture site with less contents.