I started looking into AWS about just over a year ago and decided to get AWS Cloud certified. They have made some great services and serverless technologies in the last few years and continuing to do so. They also have some great AI/ML services for you to get started with. I was between going immediately for the AWS Developer/SysOp Associate directly and/or to do the AWS Cloud Practitioner first.
Think the AWS Cloud Practitioner is great for everyone, even if you are already a cloud engineer. You don't have to study for this exam too long but gives you a great overview of what AWS can offer and as well goes into Billing and Costs and their different plans. You will get more comfortable with AWS and this will help you when you go for your associates certificates.
If you have been working on AWS for a long time already and now looking to get AWS certified I would suggest then to go directly for the Associate levels instead of the Cloud Practitioner.
I would suggest anywhere between 2-4 weeks depending on how you're on time and how many hours you can commit. Try to get real in-depth knowledge of all the services within the Exam Guideline
Specially get comfortable with EC2, S3, RDS, DynamoDB, CloudWatch, Billing and Costs, RI vs Savings Plans, Shared Responsibility Model.
Udemy Practice Test
AWS Whitepapers as listed on the AWS Cloud Practitioner site
This should be enough to pass the certificate.
I started by building some simple projects on AWS to get a more hands-on experience and then went on building a little bit more complex projects. This was great to answer some questions on the exam you might not have been 100% sure on. Spend allot of time understanding EC2 instances and S3 Buckets, after you get a better understanding of them go over to the database side of AWS which is RDS, DynamoDB, Redshift, EMR etc. To get a high level of the functions of each of these. Spend some time reading the docs on Billing and Costs as this can be tricky to simulate on your account if you do not want to pay a monthly fee for services. The docs and whitepapers are more than enough to pass this exam.