SMS messages and voice calls are already collected and monitored. So would services like Google Voice (VoIP) give you at least a payback for your already tracked data?
Compare:
Using a carrier: data is collected, you only basic SMS & calling experience
Using Google Voice: data is collected, you get your SMS on your email, can call over the internet, and you can turn on airplane mode without missing a message.
It should not be an issue if you are using a VPN because all the cellular provider are seeing is that you are just connecting to one service and nothing else.
I would rather use something like jmp.chat, which has all those benefits but I trust them a lot more than Google (see their privacy policy here: JMP: Privacy & Transparency Statement). They also now have an eSIM for cellular data that has served me very well and saved me a lot of money.
Regarding services blocking you for using a virtual number - one trick is to get a real number (maybe via mint mobile or something) and transfer it to a virtual phone service. It will take some time for companies to realize that your number is now virtual.