Not a therapist, but would probably switch my life with yours in a second. I am the same age as you, in tech in a third world country and working two jobs and eighty hours a week to afford a good future for my kids. I will have to probably keep doing so into my fifties to give them a good education. Bottom line, it might be a matter of perspective.
Wondrium/The Great Courses has a number of good quality courses on Anthropology taught by renowned professors from the US. I have a subscription and a passing interest in anthropology that has been satisfied by the above. YMMV.
In my experience a better question would have been.
"Have you worked hard on something that DID pay off???"
Most of the things that we work hard on never pay off except in terms of learned lessons.
I am working as an architect with about 17+ years of experience and i feel the same. However it would still be prudent to practice as mentioned in one of the comments. Things seem easier if tackled before. Your task should be to create the time and the motivation for regular practice.
Synching up is a challenge. I am remotely managing a team of mostly young, inexperienced but highly motivated individuals at a very early stage startup. I have to spend a lot of time on calls and in chats to understand their individual contexts, coordinate work, provide guidance where necessary. I also sometimes am late responding to their queries over chat when busy with technical work, which adds to their problems at times. I also find that i have to put in a greater effort to win and keep their trust and that even small mistakes at my end create a greater trust deficit which needs to be breached somehow. There are times when i feel that i am not doing justice to the team and that it would be easier for them to be managed by someone who was colocated with them.
Are you able to understand and translate the content and context of client requirements?
Are you able to translate your understanding of client requirements into software and database designs that scale and adapt with time?
Are you able to add measurable value to your client's business by leveraging your technology skills?
Are you able to write code that is understandable and relatively bug-free?
Is your code easy to change?
Do you have a holistic understanding of the technology stack you are working on including the database platform, development platform, deployment platform?
If you do then you are doing significant work and are probably amongst some of the best in your field. It is not the label that matters when it comes to skill. It is the output that does.
If you want a broad overview of how RDBMS work under the hood, "Designing Data Intensive Applications", would be a good conceptual start.
This could be followed by database internals books like "Expert Oracle Database Architecture" and "Pro SQL Server Internals", irrespective of whether you use these databases or not, you will learn a ton of stuff about database internals and system design.
If you are interested in database schema design etc, then look up "The Database Model Resource Book" Volumes 1,2,3.
None of the above are quick reads but they are solid foundations for becoming a well rounded DBMS professional.
I go for a short walk at the end of every hour. I have found my fitbit pretty useful in reminding me to do at least 250 steps every hour. The number might be small but i usually end up doing more than that once i get going.
What about time to learn? I am one of those older average devs stuck in small scale design and development tasks that start to feel like a burden when you are on the wrong side of 40s. Time or lack of it seems a bigger factor right now as compared to the points mentioned in the article. Finding time to learn something new while fulfilling one's responsibilities in life while trying to desperately hold on to the current job feels overwhelming. Time management in short might be more useful than all the other things combined. Or maybe i am just an old geezer.
Sane words. However sometimes life pressures like building a nest egg for a family while advancing in age and having to support them through a tough (non US) economy, with few jobs sharply reduces available options in similar situations, piling up the misery.
Consider acting as a complement to another already established vendor in the target market. Do they have a weakness in their offering that you can help patch? Are there features you can offer that will enhance their offering's value?