You can try UltimateWB software free on our Demo page: https://www.ultimatewb.com/demolinks .
UltimateWB software is very powerful software, and very flexible - it is what we use for our website too. You can use the Ad(d)s Manager to embed third party plugins, etc.: https://www.ultimatewb.com/adds-app/adding-google-ads-media-plugins-analytics . You can also add your own custom coding.
Not sure what you mean by referring to Shopify - Shopify is a hosted web solution for creating your website. You can actually find a lot of comparison charts under our "Compare" tab on our website, including a chart comparing UltimateWB to Shopify/other e-commerce solutions here: https://www.ultimatewb.com/e-commerce-website-builder-comparison-chart .
UltimateWB Full comes with built-in e-commerce apps you can configure and customize the way you want, i.e. you build your own "template".
You might want to check our Video Tutorials for a good idea of how UltimateWB software works: https://www.ultimatewb.com/video-tutorials .