max altitude

Greetings! I wish to pick the collective brain of this audience. I'm a US certificated drone pilot, as well as hold a sport pilot license. My question regards the "maximum" altitude that I might fly my drones. Following is the pertinent (I believe) regulation: § 107.51 Operating limitations...

Hi Folks, I work in archaeology in the Andes (6,000 meters max) so the question is what is the maximum altitude for a Thunder Drone? I could be working at 5,500 meters or more where the air is quite thin.

I have just learned the hard way that newer models of mavic pros (with initial 1.3.1 FW or newer) cannot be simply downgraded, but must also be disassembled and an extra micro sd card must be inserted in order for the drone to work. Otherwise you will get "cannot take off message" and sd card...

Understanding the US 400' max. altitude, can I legally fly to the top of a local TV tower that is 800' tall to shoot a 360 panorama image? There sure won't be an airplanes anywhere near it? That could be an interesting shot. If it's legal, does DJI limit my flight to only 400'?