I'm a bit older, but can relate to the "lost interest in software" because of the uselessness of most software I see around.
I look at the job ads and for most of them: 1) I don't see myself fitting and/or 2) I could not care less for what they are doing.
So trying to look deeper into my soul, considering something on the verge of software and hardware, related to helping humans, or trying to get to academia.
I don't have a solution for you, but for sure, look deep inside you - if there were no social / financial / ego constraints and the possibilities were endless, what would you choose?
Also curious about a post-mortem - come back to share here when you've figured out.