In the US, porting wireless numbers has been mandated by the FCC for almost 20 years. I'm feeling my age, as I remember being excited during the process and when it finally happened.
https://www.fcc.gov/general/wireless-local-number-portabilit...
I think you can also do that with an iPhone and the Google Smart Lock app.
That said, I do keep a Yubikey with me in my bag when I travel in case my phone breaks and I need to authenticate into a new device. I do take a Yubikey with me going to and from the office as there are other services and platforms which do challenge my Yubikey more often.
The only downside is that Google is the only site I used that supports it.
If you buy a Titan Key you get two (USB-A, USB-C), so sticking one of them in your safety deposit box, locked desk drawer at work or another secured space is a good backup.