cloud security - This vast topic, depends on requirement, start from small to major deployments, what kind of security you looking, what services you looking to go to cloud.
Some compare in the market :
https://www.tripwire.com/state-of-security/security-data-protection/cloud/aws-azure-google-difference-cloud-security-standpoint/
https://securityboulevard.com/2021/05/aws-vs-azure-vs-google-cloud-comparing-cloud-platforms/
Again this give high level, it all business requirement, there is no Security product available from Thousands to million cost - based on use case.
Business to define, what to secure, what kind of visibility looking to address security domain.