According to Canalys, GCP is at 6% cloud market share (in dollars), Azure at 17.4% and AWS at a bit over 32%.

https://www.canalys.com/static/press_release/2020/Canalys---...

AliCloud and Rackspace are very close to GCP as well.

That being said, if you're planning on running Kubernetes, I'd choose GCP over any other offering - the tooling and support just seems better, in my entirely subjective opinion.