Hi Rafael!
Great question, it’s surely something most vanlifers etc will have to deal with at some point. Most properly use their phones hotspotting. That’s good, but does rely on your phone, will drain battery so you need it on charge most of the time etc, so not my preferred method.
I would normally recommend getting a dedicated 4G/5G modem that can sit permanently in the van with a data sim in it. Then you’ll have wifi all the time. Or at least where theres signal. π
On that subject, I am actually writing an article on Starlink right now, that hopefully will be out soon. That’s the other solution. Starlink is satellite internet, and it works just about anywhere. It’s pricey but very very handy. So I have both a 4G modem as well as a Starlink with me in the van, and as a emergency backup I can share the internet of the phone. That covers me just about 100% of the time. π