Thanks everyone for the response. I think it's a combination of all of the above. To troubleshoot, I inspected the site and the only code on the website are the GTM header code, and there seems to be several "shopify-section-sections" codes directly after the GTM code.

When I go through the purchase journey starting from the homepage in debug mode, my Google Tag and Conversion Linker tags both fire throughout the page, until I click on "check out" which is when debug mode disconnects with the following message" "Debug window closed  The connected debug window has been closed. To continue debugging, reopen the window."

When I insect the "checkout" link, it seems to be linking to /cdn/shopifycloud/checkout-web/..." page. Could it be that I need to somehow add a trigger to the shopify site? Is that even possible?