Also, as a non native speaker you will have a harder time getting a work visa for teaching English. It was easier over a decade ago but near impossible now (unless you get hired for a different role related to your degree and then proceed to teach English anyway).
Age, looks and sometimes even gender could indeed be a decisive factor. Other things that can help are your connections and circle you have built over the years, but that may not apply since you came over from another province.
Sucks your original plans got folded due to the virus. Good luck with job hunting.
It's not about probability of someone ratting you out, that is probably low actually. What could happen is that authorities do a crackdown on foreign teachers working in schools and from there on discover any illegal activities.
Recent semesters things have tightened up with more check ups in school even in a smaller place like Kunming.
As Liumingkie mentioned, the age could be an issue for a contract to begin with as well.
I went to Xihua park both yesterday and the day before without any more checks or measures than the Chinese visitors there. I've entered shops the recent days (supermarkets, pharmacies, restaurants) without any hassle.
Noone stopped me randomly on the street to check my temperature.