It has nothing to do with configuration.
It's all described here:
https://stackoverflow.com/questions/52377469/failed-to-open-the-referenced-table

I understand that you are showing me "why it doesn't work".

I just don't understand - "why it doesn't work from the admin panel of the purchased product", and "why should I solve this issue myself"?

I ask you to check the situation, as you said.
Do you need the database dumps I mentioned earlier?

"why it doesn't work from the admin panel of the purchased product"
It's not related to plugin, as plugin only can ask DB to create foreign key. Not to tell export function what is order it should export tables. That's in hands of export functionality.

"why should I solve this issue myself"
Because you use open source software, including database one.