Learn Cloud Computing for carrier improvement

I am a senior develop in Java and have 14 years of experience and have not worked on any cloud technologies. I am interested to know which cloud platform to learn and what I learn and any free resources where I can ?

Core AWS Services to Explore:

AWS Lambda: Serverless compute service to run code without provisioning or managing servers.
Amazon S3: Object storage service offering scalability, data availability, security, and performance.
Amazon EC2: Scalable virtual servers in the cloud.
AWS RDS: Managed relational database service for MySQL, PostgreSQL, Oracle, SQL Server, and more.
Learning Resources:

AWS Free Tier: Experiment with AWS services at no initial cost.
AWS Training and Certification: Access tutorials, documentation, and labs.
Certification Programs: Consider the AWS Certified Solutions Architect – Associate or AWS Certified Developer – Associate for structured learning.
Online Learning Platforms: Utilize A Cloud Guru, Coursera, and freeCodeCamp for practical courses.