Welcome to the dark side, we have the best of all worlds (YMMV!):
At work I'm currently porting a large project onto .NET Core / Linux from .NET Framework / Windows, so we can component-ise & scale it in AWS or other public cloud hosting - it's fun!
Advice (with a pinch of salt): always follow your interests, read widely, learn with a purpose (set a goal, solve a problem at home or at work) and only measure yourself against you yesterday, never others. Find your own pace & find a mentor!
Personally, I've grown up with the changes from the early 80's (eg: worked with VMS, MS-DOS, Windows, MacOS, Solaris, Linux, while learning C, ASM, Java, CS theory, C++, Perl, Python, Ruby, C#, Rust, Go, design patterns, ...) thus my learning has only had to keep up with the technology, not catch up! My learning has always been in bursts, driven by immediate need, to pick up the useful 20% of a technology, then if I continue to use it (hello vim!) I slowly learn the remaining 80%, while trying to make real use of it. What I found for me is that I learn best focussing on one thing at a time, eg: working through the basics of a language such as the dive-into-python course, or reading through a good book on database refactoring (no really), then applying it immediately to something concrete - this either helps it stick or I decide it's not going to work for me - failure is an option :)
As Phil Ashby said, you can use .Net Core on Linux. If you add Visual Studio Code in that equation, you will have a very good experience :)
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