The old terrestrial MW networks of the telcos were C-band 6/4 Ghz. They used to use passive plano-reflectors for terrain problems. Thus, I can’t see how 5G 6G, at even higher mmW frequencies, will penetrate a sealed, heavy-duty enclosure, let alone a Faraday bag. Its been a long while since my tech days, so I may be out of touch.
Yep, and that’s why Wi-Fi 6e is “son, you’re on your own.” it’s shared spectrum.
Telco/cellular C-band is still ‘owned’ for military RADAR, and unless you buy an expensive ongoing license, your zippy new C-band CBRS private 5G network can endure a lot of interference from nearby permitted use, even other private 5G networks, and it’s “tough noogies” for you.
Cellular radios and towers are VERY low power compared to most other applications. So yeah, *IF* you put your smart phone into a microwave oven your RSRP/RSSI/RSRQ are so weak/ poor that you’re never gonna connect and you’re likely safe.
The same is true for an old metal Charles Chips can.
All depends on what threat you are protecting yourself and your devices from.