I gave a talk about using the amateur radio IP network and a VPN at DCC this year. See:
With or without the VPN, I like to operate sometimes away from the WiFi or a wired Internet connection.
I often use this little router https://www.gl-inet.com/products/gl-mifi/ with Google Fi service (US ATT model) -- I just saw they have a 25% off holiday special. (This model should also work with T-Mobile and ATT networks with the proper SIM and plan).
If you want to check out Google Fi (who will provide free SIMs to customers for this type of device, sharing the data plan with the account) -- use https://g.co/fi/r/C622J1 and get $20 credit after 30 days. (I do get a referral credit, if you use the link or they are offering an equivalent 30 day free trial)
Neither I nor NW Digital Radio are affiliated with GL-INET or Google Fi. I am just a satisfied customer of both of these products, and passing along the information.