FX Builder is not a Page Builder, true.
In my decades-long experience, the hardest thing to do in the TinyMCE editor was columns.
So, FX Builder helps with columns. This was a huge help for 3 CP websites I worked on. Everything else is doable in-theme, or by using shortcodes, or other plugins.
I have also built an even more bare-bones editor, which helps me a lot. It’s personal preference. I want my websites to be fast and light.