Technically no, but practically, yes. You can use GTM without using data layers, but if you do that, you won't be able to pass specific data (e.g. product ID, name, order total revenue, etc.).
You can only use the general tags like Google Analytics 4 - which works on all pages. However, you can't use Google Ads Conversion Tracking properly, because you again need some information like the order ID, revenue, currency, and a few others.
Analyzify provides [open-source data layers for Shopify merchants](https://analyzify.app/google-tag-manager-shopify/datalayer).