What is the recommended practice exam tool (ex: measureup and udemy)?

As of November 19, 2021, all new AWS Certification practice products are available through AWS Skill Builder.

There is no one 3rd party resource that is recommended. There are many 3rd party resources available, each with their own strengths and weaknesses. Personally, I've used Udemy, acloudguru, and Tutorials Dojo successfully.

https://aws.amazon.com/training/digital/aws-cloud-practitioner-essentials/