I'm just going to play the devil's advocate for a second and say that if you feel like you don't understand the "infrastructure" side enough, don't start by learning one proprietary cloud service like AWS, or one extremely complex orchestration engine like Kubernetes.

If you are a developer, you will (likely/hopefully) not be managing Kubernetes clusters anyway, so you don't need to know all the plumbing. Same thing goes for AWS or Azure or whatever, your $CURRENT_WORKPLACE will (hopefully) have duct tape in place to deploy to these things.

If you want to become a more valuable developer, learn the basics that are true everywhere. Linux is Linux, and Docker is Docker, so start with that, and understand how to tie them into CI (in whatever platform you use).

Being a developer that can actually troubleshoot platform issues is much more valuable than being a developer that knows every single service offered by Amazon.

And if you lack motivation, do what everyone else does: start self hosting.