Hey, thanks for using the plugin! So right now the plugin will remember the last block you made, and when you add a new one it will carry over (most of) those options you set. So in this way, it will kind of act like a global setting.
WP recently added global block styles, but not for custom blocks. When they do, I want to add some styles there that will apply to every block. This will only affect some options decorative options that don’t involve data processing (so themes wouldn’t work here – fonts would)
There’s no good way to globally apply a theme across a site either since it requires some heavy processing to be done per block (it happens as you type, actually). I thought about adding an admin page that could scan every post and do a massive in-browser update, but it’s a bit of work and not sure how useful it really would be. The ETA would just be when there’s a lot of demand and I have time.