GPL does not contain the words "dynamically linking". That‘s just a common interpretation as a shortcut.
In this case there are arguments for the program-plugin communication to be "intimate" and as such falling under "derivative work". But it‘s easy to take the other side, as well.
GPL license in spirit is about assuring the user freedoms. No user freedoms are limited in this case. You are free to modify and redistribute the software as you like. OrcaSlicer pulls changes from Bambu without any issues.
I don't think trying to enforce the license in this way, even if possible (which again I think if it was it would happen with Linux drivers long before), is the right thing to do anyway. All it's doing is painting the GPL as a liability to any business for no benefit.