Not sure if you’re aware but gSender has a laser offset to help with aligning the laser zero to where the router zero was and vice versa.
I was just posting about it here. Not sure if that helps. Some people here use macro’s to go back and forth between laser and router.
Your workspaces solution will probably work but will limit you to that one place for zero if I am understanding correctly. As far as how they work you can change between workspaces in the top right area of gSender. Any zero that is set in a workspace will stay set until you set it to somewhere else. They are saved in EEPROM and persist through power off etc.
For example I have saved my router position at the center of my machine to the last workspace. I can turn on the machine, home, switch to that workspace and hit Goto XY and my machine is in the center. I can then switch to any other workspace and Hit zero all to copy the position. With some peg holes drilled from that center position I can do double sided work. I never work in that last workspace I just use it to store center.
All that said it would probably be easier if I just took the time to learn some macros for gSender.
However you achieve it, I think it’s beneficial to be able to get to the same spot repeatedly.