Someone wanted to learn this too, so Grasp built them a personal learning path.
You can keep exploring this one or create a path like this one shaped around you.
Recommended resources
Module 1
Containerization Foundations
Module 2
Docker CLI Essentials
Module 3
Building Images with Dockerfiles
Module 4
Advanced Image Building and Optimization
Module 5
Data Persistence with Volumes
Module 6
Understanding Docker Networking
Module 7
Docker Internals: Namespaces, Cgroups, and Layers
Module 8
Multi-Container Applications with Compose
Module 9
Registries and Image Distribution
Module 10
Container Security Best Practices
Module 11
Troubleshooting and Health Monitoring
Module 12