Chosen Solution

Hi, I looking for a way to have a 100℅ offline device. Would it be possible to install on smartphone mainboard a custom switch to physicaly disable wireless components? I own oneplus 7 pro and sony 5ii . I would be interested to mod one of them. Thanks in advance

@alotanoa a simple switch on the WiFi IC power supply might just do the trick. Hardest part will be to find the schematic to know which line to use.

Just turn on airplane mode?