How to find the public microwave closest to my home?
No, there is no danger. All EM fields on the outside the microwaves are very weak. There is no danger or risk.
Microwaves look like visible light waves, with the exception of the larger ones (the "micro" is in comparison with other radio waves). Both are non-ionizing radiation; they do not have the energy needed to move the electrons in the atoms. And, just like visible light, microwave radiation follows the law of inverse squares and decreases dramatically as you move away from it.
Microwaves use exactly the same radio waves as Wi-Fi, except with higher power and concentration. However, the microwave box keeps this confined. In the United States, federal regulations limit microwave leakage to 5 milliwatts per square centimeter to 5 centimeters from the box for microwave leakage throughout the life of the device (ie not only if they are new). For comparison, the FCC limits WiFi routers to 1,000 mW (or, you know, one watt). And you should not worry either.
Is there a physical flash method, for example, put your phone in the microwave and blast it?
or send it by MRI?
I've isolated the problem related to my phone to 4 applications: the "Android" browser preinstalled, the fake-Android launcher, the fake Android-free update and the pre-installed gangyun beauty capture application ; and a potentially problematic "media" file that is preloaded, Jar_of_Love.mp3 (just because this song is so monotonous, tasteless and lacks creativity).
It would not bother me to root my phone if the aforementioned ETs did not call home (China) all the time.