We have some client’s sites, where using 2 or more designs in one website. (It is better solutions in this case than using subdomains).
In bricks builder, I can make more themplate sets and using conditions where and when using theme.
It would be great, if I can do this same with coreframework.
This would be a Template builder feature in my opinion and should not be part of core. Core should remain as a consistent base layer for dynamic typo, gaps etc. for all template builders.