A: It depends of what you are talking about: the builder ? or building RTL websites ?

The builder is not RTL now: English only and the interface doesn't change sides (for example moving the left sidebar on the right side of your screen and so on)

Building RTL websites.
Yes, easy.

Regarding the language, you can upload your own fonts and it is off to the races.
As for the alignments and design, you have all the tools in Brizy to create a RTL website.

If I'm not missing something, that is it.

Let me know if I can help with anything else.