In reply to Nick.

As Andrew said, the Button CSS is not hardcoded. It's created using the standard block options. But, that does bring up an interesting UX issue that I had not thought about. If users expect the same-styled button, they cannot get it by clicking the "+" icon to add another.

They must either recreate it themselves or duplicate the block (assuming the user knew how to duplicate). This is also the same issue without choosing custom color and border options. Simply selecting a block style like Fill vs. Outline would result in the same behavior.

For the Real Estate block, you could technically save content as metadata. However, I would create a CPT instead. Then, create a custom Real Estate Search block for advanced searching of metadata, terms, etc. I can't think of any good reason to try to encapsulate all of that into a single block outside of a site that showcases more than a handful of properties at a time.