Victor Ramirez talks about the approach here: https://www.youtube.com/watch?v=3o66SvY9G1k&t=91s
The plan itself was posted on Twitter. It is a bit old, but it sounds like decent approach
Level 1
- Style the editor and core blocks to match the client theme.
- Disable custom colors & fonts to keep the client on brand
- Disable all core blocks your client doesn’t need per post type. Too many options are confusing. (Optional)