WYSIWYG is one of the WORST website builders I’ve ever encountered. I tried using it once a few years ago, and it was just terrible. I would stay FAR away from it.
I’m not familiar with Webacappella Grid, but the sample site I examined had pretty awful code as well. Tons of inline styles and unnecessary nested divs.
Over the last 10 years, I’ve come across precious few website builders that output clean, semantic code. Pinegrow, of course, is one of them, and if you’re serious about building websites, it’s worth it to buy the program and learn how to use it. Not easy, but worth it.
Bootstrap Studio is another program (my personal fav) that produces perfect code. While it is not free, it is very reasonably priced, but there is a bit of a learning curve. You don’t (can’t) edit the HTML, but you do need to know CSS to do anything fancy, and having a basic understanding of how HTML and CSS work is kind of important to really get the most out of the program. It has pre-made blocks, and fairly easy-to-use visual tools to customize most components. Bang-for-the-buck it can’t be beat.
The next program that I know produces clean code is Webflow. Webflow, however, is a cloud-based program that you must pay a monthly subscription for (if you want to be able to export your site’s code, there is a free version with no code export.) There is also a learning curve involved in using Webflow, though it is a very polished and well documented program. Webflow uses CSS grid, not Bootstrap.
While I have not used it, the program Wappler supposedly produced clean semantic code. It’s is also fairly expensive, and there is a significant learning curve involved. Wappler was designed as a back-end, PHP type builder, but it also does front end sites.
The only free program I can think of that might be able to do what you want, and which will produce decent code is Mobirise. It’s a drag-n-drop Bootstrap builder, that caters to non-coders, but as with any website building program, if you can’t touch the code, you will be limited in what you can do. It has paid modules that unlock aspects of the program (like being able to edit the code.) Some people rave about it. Personally, it’s not my cup of tea, but it might work for you.
There’s also CoffeeCup website builder, which supposedly produces clean code. It’s not cheap, but it does have a following. I’ve never used it, so I can’t really comment on how hard or easy it may be to use.
Hope this helps you a bit.