In the last 5 years there was NO WORDPRESS THEME OR PLUGIN that I didn't have to modify. I never saw any WP theme that comes with minified CSS/JS, handles sidebars correctly - sidebar created after post content, generated by PHP not JS, generates correct <a> tags, even one "modern" theme had links in sidebar with "nofollow"... "SEO-friendly" plugins that make blog generation time 3-5 times longer than before, of course JS not minified, jQuery and fonts linked with ?version=xxxx (prevents server and browser from caching it), social buttons that were downloading ~1MB of scripts and CSS (for Facebook, Twitter, G+ and Pinterest).
Whole WP ecosystem is a huge pile of crap, each plugin adds more and more mess to it. I tried Hugo and Joomla, but they were even worse (Joomla had a few security issues that developers refuse to fix, Hugo was more bloated than WP).
After trying and modifying over 20 acceptable themes I decided to start working on my own blogging platform that will be SEO-friendly and clean.