Deutsche Telekom used Huaweis OpenStack implementation.
I haven't found any information that this changed, so I assume it is still running completely on Huawei. At least they made sure that they still get chips from the US despite sanctions. ;-)
Basically it's just Openstack with some customizations. The rest of our customers run on gcloud. I'm currently eyeing Hetzner as I want to lower our hosting cost.
But the point of Openstack is that it's generally fine and that the feature set it offers is a commodity. AWS definitely overcharges for this stuff. If you do the math, most of their vms will cost you the hardware it runs on within months typically. Amazon runs this hardware for many years. In some cases they host multiple vms on them. Their margin on this stuff is huge. That's why they are so rich. You pay for the convenience and the uptime of course. But undercutting their pricing profitably isn't that hard.
Haven't talked to the guys for two years, so it might have improved in the meantime, but it's Telekom, so I heavily doubt it.