It depends on the theme. If you are doing a simple blog theme which basically doesn’t even use standard pages then you don’t need the page builder (however such theme would have to be super premium and well done to be even approved). For anything more complex where you need to edit page content, you will need a page builder.
Nobody is going to bother with shortcodes anymore. Especially when the block editor (Gutenberg) is the native part of WordPress. You may be lucky to sell few licenses to some “old timers”, but you can’t build a business on that. It doesn’t really matter what you prefer, if you want to sell, you need to do what customers prefer. And if you actually want to succeed in this business, you need to learn to embrace the change.
Not sure how exactly you plan to use ACF so I can’t answer your question about it. But if you are trying to somehow allow users to edit content of pages via ACF (instead of using a page builder) then it sounds like a very bad idea.