I am sincerely wondering if this must be the case or is it a shortcoming of the existent solutions, but something that can be overcome. (Disclaimer: I am a programmer who never seriously used any low code product apart from a spreadsheet. Unless you count Emacs as a low code platform, which would not be wrong, I guess.)
I think it's intrinsic to the problem. That 20% long tail of the customer's problem is not just different for every company, it takes a decent programmer to recognize where that border line is.
As a result these solutions work just fine until the point where they trip the user up and start repeatedly punching them in the face. The user will usually try to work around the limitations and that's when it goes really badly wrong. Often the users will blame themselves for not knowing how to progress or for creating a mess.
If your needs are simple enough you might never reach that border. It's suitable for those tasks.
It's made worse by the economic incentives of no code platforms too. They try and trap the user on their platform. So, once you reach the border line the user usually has to dump the entire app and bring in a programmer to code it all up from scratch. That makes bad workarounds that much more tempting from the user's perspective and thus that's how the no code solution dumpster fires are born.
