Template Framework and CSS extension

Hey Ho Guys, we are at the moment thinking about purchasing one of your themes, most likely the Zubin Pro. Since the range of widgets you offer isn't quite enough for our use case we want to add our own code snippets to the theme. My question would be: do you use a framework like Bootstrap? And also do you use a CSS extension like Sass or Less? If yes, is the extension file available? Another thing Im wondering about is your support for the Guttenberg Editor. Themes like the Alchemist Pro is listet as a Block Editor supported theme at Wordpress. How far does that support go? Since your content blocks are customized in the theme options itself. Are they still available as Guttenberg Blocks? - little bit confused right there :D Thanks in advance Tecwriter