Hello,
Our members use all different kinds of builders, and we don’t feel the need to recommend any specific builder. Every builder has plusses and minusses and ups and downs, and we can all expect some learning curves ahead with the addition of Gutenberg to WP Core, which is itself a kind of builder. If we recommend something, I would say it is closer to general advice to continue to build skills with HTML and CSS and to avoid dependency on a builder. Builders often include huge amounts of additional JS and CSS, all of which ‘can’ slow page load speed. Plus you end up with a site riddled with shortcodes that can’t necessarily be replaced directly and where CSS used with inline styles might have done the trick.
You can keep using that builder, or any other builder, but you will need to speak with the builder author about how to use it to add widgets or shortcodes with the builder.
The issue here is that the builder has some specific instructions for using widgets and shortcodes. This is true for most builders, that each one has specific instructions. The builders have specific instructions because otherwise the builder outputs a huge amount of CSS and HTML that (slows the page waaaaay down and) often has an unintended effect (read:butchers) the output. This is just ‘how it is’ with builders in a lot of cases, that a couple extra steps must be taken to use them, and I have yet to see one that doesn’t require something to that effect.
Other members can chime in if they have had good experiences. Some have mentioned Kleo, in the past.