I'll be 57 in 3 months. I've been coding professionally
for 35 years.
The past is just a memory, the present moment is so fleeting that it cannot be grasped, and the future hasn't happened yet:) I think being in a flow state is about living with this fact, in the moment, as it is, without all the mental overhead that is past and future. You're not 58, you are brand new, right now, just as you are.
My very first paid project was designing the PA audio system in the Lille (france) metro. It was a fancy Mac SE/30 with a IEEE GPIO card. That was driving two big Revox Tape machines, and was playing one, rewinding the other etc. Occasionally it would also play a digital audio file (w000t!).
It was all in Pascal at the time, and I had a whooping 4MB of ram. System ran for well over 10 years!
On my first internship after high school while waiting for university applications to come out was done in Clipper and Access/Visual Basic. Also starting OS/400 backup jobs.
Not the set of languages that I already enjoyed most, but it kept myself busy during the Summer.
I can't imagine having done anything else. Sure, many other careers sound appealing. But software has been stimulating and sustainable while affording me a managable level of stress and downtime as needed. (Try doing that as a physician or veterinarian, both careers that I once considered).
That said, I sympathize with the OP's frustrations. Software jobs usually imply a rather flat hierarchy, with little opportunity for advancement other than leads or principals. Any further rise in responsibility requires that you leave tech behind and spend your days in meetings. Not for me.
However if you work in R&D without a PhD, I've found a severe glass ceiling (especially at larger companies). In general, no advancement beyond lead staff for you. If I'd known that 10-20 years ago, I would have handled that differently (get a PhD, work at smaller firms, or leave R&D). The road not taken, I guess...
It's hard to beat the feeling of having a computer make your life easier. There's a triumph in it.