John has WiFi in his truck and it goes in and out. Would using his cell hotspot fix that? Leo says no, dead spots are in between cell towers, which can cause your cellular signal to go in and out. That has nothing to do with WiFi. The only way to avoid it is satellite, and that has its own challenges with maintaining the aim of the dish. The real solution is what ISPs have the best coverage maps. But a dead zone is a dead zone, and until the cell company puts up more towers, you have to live with it. How about a cell booster? Leo says it could help, but only marginally.
Will 5G fix it? Leo says not initially. In fact, it may make it worse. 5G doesn't travel well, which requires more towers. So again, the answer is more towers to eliminate the dead zones.