We are often blinded by these fancy Block editor that we forgot our root, which is shortcode. It's not a good root, but at least it served us well.
If you have an ACF Repeater Field, try replacing it with a plain HTML Table. Other than being easier to edit, I believe the performance is better.
C9 Blocks plugin comes in handy with its pre-loaded page and section templates to speed up the process of building page.
There are a lot of plugins to disable Gutenberg editor. But the code to disable it is actually very short and simple. So no need for plugin, just add this snippet in…