Hello C3rr3,
Unfortunately, it is
not possible to retain the current value of an exposed parameter when resetting a parameter.
Since you mention copying and pasting nodes across several graphs, have you considered using node
instances?
You can create a graph that carries the functionality that you need, and plug this node into your other graphs as required. Just drag and drop a graph into another one!
Additionally, if you need to copy and paste parameters, you are able to import and export presets.
In the example below, a simple node floods the material with water, with some exposed parameters:

The 'LG Water Flood' graph. Several parameters have been exposed.

The 'LG Water Flood' node in use.
We hope this is helpful. Feel free to get back to us if you need further assistance.
Best regards,
Luca Giarrizzo