Two questions upfront.
If the answer to both of those is yes then you could consider using the guest mode as your VPN network.
If not then your best option is probably 2. You could get a router which supports OpenWRT or use a different enterprise style router like pfsense.
I the same thing you're asking about in pfsense where I routed one VLAN over a VPN while leaving my main LAN completely normal.
Oh yeah, got rid of the damn thing within 30 minutes of registering but it was too late. I assume bots grab that info as soon as it's posted.
Probably got pushed to the larger system.
There's more than one entity that controls WHOIS information. Typically as soon as WHOIS information gets published it gets copied into a bunch of different registries so you have to contact them all and have them remove the information
Both. I have things that I host simply for fun, but most of my homelab is for experimentation.
I practice with different technologies so I can try to learn how they work.
Why not just use the Cloudflare Tunnels command line binary?
It can automatically create the CNAMEs