When you're viewing your Shopify report called "sales from marketing" (not available with all levels of Shopify) to see the total revenue from Google Ads, you'll likely see a lower quantity than what Google Ads reports.
It's not unusual to have a 20-30% loss in conversion value when in Shopify's marketing report when compared with Google Ads.
The lost conversions can be attributed to two things:
Shopify uses UTM parameters, which are often dropped, whereas Google Ads uses a robust tracking algorithm.
Shopify removes conversion value from the reporting if the customer made a return, whereas Google Ads doesn't know about the return so it doesn't get removed from the dashboard.
Here's a video Kasim made on this topic -- Although the video talks about Google Analytics reports rather than Shopify reports, it's still the same phenomenon, because Google Analytics also uses UTM parameters: