GCP has billing alerts, and a cap. But it can take up to 24 hours after the cap is hit before you stop receiving new charges in some case so it isn't perfect.
Not sure about Google, but Azure has it with some subscription types but not all.
I have an Azure subscription that gets some free monthly credits. When I go over the limit on that subscription, everything freezes until I sort it out.
Most Azure services don’t, but Azure Monitor does. I guess it’s easy to deploy something that emits tons of logs or metrics inadvertently, so having a quota might be nice.