In Wordrpess, how can I insert a builder into a theme block?

Question

WordPress

We need to make up a theme, everything would be simple, but the customer wants a piece of functionality like on the previous theme. The previous thread used Builder https://wpbakery.com/ . You need to make one block in the builder. To what extent is this option feasible? What would connect the builder not to the entire site, but only to one block?
(I’ll say right away that I don’t really like builders and haven’t worked with them for a long time)