I do conversion rate optimization for ecommerce and Baymard is an extraordinarily valuable resource. If you're doing any work in ecomm or b2c, it's well worth the premium subscription price.
I think most ecommerce problems stem from these things:
1) Too much reliance on platform's opinions / defaults or the inability to technically overcome the usability concerns the platform presents for your implementation.
2) Uninformed design decisions. That is decisions that aren't backed by user research, data, etc. While ecommerce stores share tons of commonalities, the product offerings are unique and present different challenges/needs/etc. from other shops.
3) Brand getting in the way.
Baymard is a big boon for #2 because it takes data that is very expensive to get and makes it easily and cheaply accessible. Rather than focus your research efforts on large-scale ecommerce concerns, you can focus them more on your core differences. It also helps provide justification for #1 and helps inform difficult conversations about #3. Self-servingly, I'll say that CRO work helps take these things a step further and provide further validation or help answer difficult questions before investing too many resources.
At one point I also specialized in conversion-rate optimization for some very large eCommerce sites. If you can easily afford these, take advantage of them. There is no clearer guide for how to take a large eCommerce site from mediocre to being well-optimized for conversion.
I think most ecommerce problems stem from these things:
1) Too much reliance on platform's opinions / defaults or the inability to technically overcome the usability concerns the platform presents for your implementation.
2) Uninformed design decisions. That is decisions that aren't backed by user research, data, etc. While ecommerce stores share tons of commonalities, the product offerings are unique and present different challenges/needs/etc. from other shops.
3) Brand getting in the way.
Baymard is a big boon for #2 because it takes data that is very expensive to get and makes it easily and cheaply accessible. Rather than focus your research efforts on large-scale ecommerce concerns, you can focus them more on your core differences. It also helps provide justification for #1 and helps inform difficult conversations about #3. Self-servingly, I'll say that CRO work helps take these things a step further and provide further validation or help answer difficult questions before investing too many resources.