I personally have a similar background to you, with ~15 years of software engineering.
I second some of the comments: I really started understanding quantum computing much better when I sat down and worked through the problems of the Nielsen and Chuang book ("Mike & Ike") - the first 4 chapters should give you a solid start. It starts from theoretical base and does cover some of the applications of QCs as well, though from that perspective there are a bunch of newer results that are not represented in it yet (e.g. QAOA/VQE, NISQ era algorithms, etc.). Some basic linear algebra is definitely needed though, it takes effort and practice to build up familiarity there if you are rusty on it (I was).
Also, I would like to plug open source contribution as a vehicle / forcing function for learning. I started contributing to Cirq (https://github.com/quantumlib/Cirq) starting last year in my free time (as well as some of my work time at Google) and I learned a ton through that. I now work on Cirq full time. OpenFermion, qsim, Tensorflow Quantum are all projects that are excited to have new contributors.
The reason I mention my journey because it shows that you don't need formal training in quantum physics to become productive in the quantum computing community (it can definitely help though). However, the field is very deep and is moving very fast, I very much consider myself a noob and rely heavily on the expertise of others for contributions, and I spend a lot of time reading and learning still every day - including other chapters of Mike & Ike, Preskill's notes (http://www.theory.caltech.edu/people/preskill/ph229/), papers and online tutorials from other platforms that can help shed light on a particular topic.
Also, don't forget to check out https://algassert.com/quirk - a very useful in-browser quantum circuit simulator written by Craig Gidney, who also was one of the main creators of Cirq. Even more inspiringly, he also, with very hard work, grew from a software engineer into a quantum researcher without formal training. His words: "My learning was heavily based on explaining things to the computer and then having the computer show me the consequences of what I explained." - he also recommends this playlist: https://www.youtube.com/playlist?list=PL1826E60FD05B44E4.
I personally have a similar background to you, with ~15 years of software engineering.
I second some of the comments: I really started understanding quantum computing much better when I sat down and worked through the problems of the Nielsen and Chuang book ("Mike & Ike") - the first 4 chapters should give you a solid start. It starts from theoretical base and does cover some of the applications of QCs as well, though from that perspective there are a bunch of newer results that are not represented in it yet (e.g. QAOA/VQE, NISQ era algorithms, etc.). Some basic linear algebra is definitely needed though, it takes effort and practice to build up familiarity there if you are rusty on it (I was).
Also, I would like to plug open source contribution as a vehicle / forcing function for learning. I started contributing to Cirq (https://github.com/quantumlib/Cirq) starting last year in my free time (as well as some of my work time at Google) and I learned a ton through that. I now work on Cirq full time. OpenFermion, qsim, Tensorflow Quantum are all projects that are excited to have new contributors.
The reason I mention my journey because it shows that you don't need formal training in quantum physics to become productive in the quantum computing community (it can definitely help though). However, the field is very deep and is moving very fast, I very much consider myself a noob and rely heavily on the expertise of others for contributions, and I spend a lot of time reading and learning still every day - including other chapters of Mike & Ike, Preskill's notes (http://www.theory.caltech.edu/people/preskill/ph229/), papers and online tutorials from other platforms that can help shed light on a particular topic.
Also, don't forget to check out https://algassert.com/quirk - a very useful in-browser quantum circuit simulator written by Craig Gidney, who also was one of the main creators of Cirq. Even more inspiringly, he also, with very hard work, grew from a software engineer into a quantum researcher without formal training. His words: "My learning was heavily based on explaining things to the computer and then having the computer show me the consequences of what I explained." - he also recommends this playlist: https://www.youtube.com/playlist?list=PL1826E60FD05B44E4.
Hope this helps!