If you want to separate them, you can create two PAGE or you can select which ones you want to import updates and just tick the box, import updates, and create a version.

You could use the Schematic and PCB Modules feature which will uniquely name the nets in each instance.

Take one or the other of your schematics as the base design from which the other can be edited.

Save it as a Schematic Module.

Convert it to a PCB, lay it out then save it as a PCB Module.

Create and save a new project and place two copies of the Schematic Module as described in the Modules section of the Tutorial.

Create and save a PCB with two instances of the PCB Module placed in it.

Edit the schematic for the Tx/Rx changes. Update the PCB.

Then you can put mouse bites between them and put a single outline round the two and panelise that.

Note that JLCPCB does not support using V-Cut lines with PCB Assembly.