Am currently learning Bootstrap 5 framework. This involves brushing up on my CSS, HTML and PHP as it all fits together with WordPress.
This follows my previous favourite, Beaver Builder. Before that: Genesis.
Beaver Builder is great for quick website builds as the page builder takes care of responsive layout (most of the time). Additionally, it’s very fast to put a decent site together wthout worrying too much about how it’s going to work.
Cons: Rather slow compared to basic WordPress site. Difficult to apply universal styles across the site unless you use BB’s Themer.
Genesis Framework:
I used this early in my development career but found it took too long due to my development skills being very much at beginner level. Skills are much improved now so I’m interested in returning to it, perhaps along with Bootstrap.