May I suggest to add a geometry node that can split a plain by a Line, which function is similar to the UI command “Knife”
I am working on some architectural / urban design related node packages, a few different requested functions are all pointed to this node.
For example, if I have this node I can easily generate an urban road network which just use a few lines to indicate road center, and also with this node I can do a lot of things with building facades.