I'll second that the best way to get better is to be a practitioner.
Part of the reason that there's not more material on systems design is because the way we design systems is highly dependent on core systems that pre-exist a new system. You can learn all the things on paper about layer 8 vs layer 4 load balancing, how to build an effective distributed cache, how to building a decentralized rate limiter, etc but all of these things are highly dependent on what exists prior, and knowing how to work in non-greenfield components reflects an internal familiarity with them.
The other side to systems design is more analogous to producing a map of the world; eg: documenting systems as you work on them. When I was a new engineer, this is how I learned systems design. Every new system I encountered I would begin to model. This had the added benefit of teaching me UML and how to make designs that highlight the important parts.
Entirely possible; I've worked in the intersection of Software Engineer and Systems Engineer most of my career, so that leads me to think maybe I'm prioritizing some of the stuff I learn and that older things I've learned have degraded. I say that mainly because I learned the OSI model very early on in my career.
Part of the reason that there's not more material on systems design is because the way we design systems is highly dependent on core systems that pre-exist a new system. You can learn all the things on paper about layer 8 vs layer 4 load balancing, how to build an effective distributed cache, how to building a decentralized rate limiter, etc but all of these things are highly dependent on what exists prior, and knowing how to work in non-greenfield components reflects an internal familiarity with them.
The other side to systems design is more analogous to producing a map of the world; eg: documenting systems as you work on them. When I was a new engineer, this is how I learned systems design. Every new system I encountered I would begin to model. This had the added benefit of teaching me UML and how to make designs that highlight the important parts.