Can we implement events like add to cart using gtm only with a shopify plus plan ?

[tfm_webmaster]

I am running google ads for my shopify store. When I run ads there is an option coming for conversion optimization. My goal is page views right now, but later on I will do conversion optimization for other events like add to cart, purchase, initialize checkout etc. I want to use google tag manager for that. But I have read that functionality for google tag manager is only available to shopify plus plan.
Does that mean store owners on Shopify basic plans can't do conversion optimization for their websites ? That conversion optimization is not required on sales channel like facebook, Snapchat when we run ads on these platforms.

I think I might be missing something here. Please let me know how can shopify basic  stores do conversion optimization for running google ads ?

[tfm_webmaster]

I understand what you are saying, and I am going to use the way you are telling. But I am not able to understand why shopify support is saying that google tag manager is not available for shopify store on basic plans