VISAS

Hi everyone,
I hope you're having a good day!
I have a few questions about working visas in Russia. I'm from the US and I work in Moscow. I currently have a working visa that I got with the help of my employer here in Moscow. I teach English here and my employer has sponsored my visa. If I were to stop working for my employer, if I were to resign from my position or if I were fired from my position, would my visa lose its validity? I would like to stay in Russia but I don't know what my situation would be like if I stopped working for the employer that helped me secure my visa. What would happen if I stopped working for my employer? What would some of my options be?
Has anyone gone through this?
Thank you!