Not if you carry a small travel WiFi router with you and have it provide the VPN link. That is:
phone ↔ personal wifi router ↔ VPN server
There may be other vendors, but something like a GL.iNet travel router running OpenWRT could be used to direct all traffic from your phone, including system traffic that bypasses a on-phone VPN, to a VPN server of your choice.
That type of travel WiFi router starts for a pretty nominal $30 or so. Your VPN may cost something per month. Or if you simply wish to alway appear to be at home regardless of where you are in the world, many home routers can provide a VPN server for free.
If I didn’t misunderstood the video you need thousands of dollars to corrupt someone to get access to SS7 and to access someone’s phone number so this kind of vulnerability doesn’t concern 99,9% of people since the threat model is at least a very rich person or a government threat. Anyway that’s very interesting to know but I don’t feel concerned by this.
Sure, the cost of entry is thousands of dollars per month but once you have access why not use it as much as you can?
I dont think these attacks are a threat only for the very rich. Perhaps your data just happens to be part of a relevant data breach. Or maybe some attacks are easier to automate (e.g. sms 2fa) so that the attacker could be looser with their target selection. Also the primary target could be someone who has access to your private information (healthcare, finance etc.).
But yes, I agree that these are better suited for more targeted, high-profile attacks.