October 8, 2018 at 5:14 pm #60818
Not really to the extend you’re talking about.
I believe the best approach you have is to build your own custom post (or see if another plugin developer has another option).
The columns block is still be developed, but in general the ability to extend or override core blocks is not really there and the recommended approach is to build your own custom block if a core one doesn’t work.
There is a styles API, but that is more CSS based than changing the markup.