as
@qwo99 said, try lower/dynamic power for the vtx and make sure you have "low power disarm" set in betaflight as heat will build from the moment you plug in. If you can shorten any of the wires, that will help with air flow, which will make some difference. I put heat sinks on my o4 75mm, not sure it helped a ton, but hasn't overheated either. The full cnc cases help, but they'd be too heavy for this. you may also want to check the ESCs, if the motors are hot when you land, something else is wrong. be careful touching stuff that might be hot though. also make sure the vtx antenna isn't inadvertently touching anything.