Definitely not humanity’s biggest problem. Chromium becoming the de facto browser creates a situation where one entity controls standards and influences how the web operates, impacting user choice and freedom, and reduces incentives for privacy and security updates.
This already happened once with IE.
I only use Firefox on desktop, but I doubt it will be a relevant choice much longer.
Edit: wrt telemetry, I was referring to the Android operating system. They collect anything and everything on users and all nearby devices.