Run for office
Start a SuperPAC
Rent powerful tools
Install three-phase power to your homelab
Rent an office
Create a mysterious alter ego
Write a book. (Fiction, even.)
Hire a voice actor / composer / musician / painter / ... (related to several ideas on OP’s list)
File a patent
Build a musical instrument… radio transmitter… boat… car… plane… helicopter… rocket…
Many counties and cities also have boards that normal citizens can join. It's usually not too hard to get on it if you can make a good case like "I live in the community, this is important to me, I have experience in this area." Good thing to do if you don't want to get as involved as running for office. You also might meet some important people in local government
Three phase? What kind of homelab?
That said, everyone can get 240 (and almost everyone does, for the washer/dryer), and I'm pretty sure that with 240 and a device (VFD?) anyone can kinda create their own 3-phase on a smaller scale.
Your employer will claim this as his own.
The employer may be right to, if you develop it on the company dime or it’s related to your work, right? If you do it on your own time with your own resources, and your employer doesn’t agree to leave you alone, then take some of the other advice in the post and hire a lawyer. Speaking from experience, having a legal agreement signed by my employer that my own developments belong to me and aren’t competing was worth every penny just for peace of mind.