The flat file Kirby CMS is a great option. The starter template has a basic blog implementation, it's easy to start modifying to look like what you want, and it has a basic admin panel for adding new pages/posts that's client friendly, unlike a static site generator. If you're not into making your own theme, there's a site for buying them called getkirby-themes.com which most other flat file CMS options don't have.
It used PHP and can run quite quickly if you setup caching and PHP 7 on your host. Content is generated from txt files that can have any number of fields (titles, subtitles, body, asides, meta info, etc).
As for ecommerce, I use Ecwid. It's a separate login to manage products, but it's also free for 10 or fewer products. After that it's a very reasonable monthly fee.
It used PHP and can run quite quickly if you setup caching and PHP 7 on your host. Content is generated from txt files that can have any number of fields (titles, subtitles, body, asides, meta info, etc).
As for ecommerce, I use Ecwid. It's a separate login to manage products, but it's also free for 10 or fewer products. After that it's a very reasonable monthly fee.