This, among other things, means that I can do a lot of things in the day + get stuff done.
I could get up early, hike a mountain, eat breakfast, put in some work, go for a run, put in some more work, go grab lunch, a coffee, and so on. But I always feel constrained by "working hours" and always feel guilt if I'm not inside my home office during daytime.
Can anyone give tips & suggestions? How do you utilize flexible work hours without guilt?
You can stop thinking of your value and productivity in terms of hours spent occupying a chair, and instead think in terms of value added to your employer's business.
* work at least your contracted hours each week
* be available for real-time interaction with the people you are working with
Track these things and make sure you are doing them and keep doing them. If you are doing all these things and in the absence of negative feedback, there's no particular reason for concern or guilt.
But also investigate whether maintaining a more structured routine is a better fit for you.
What I mean is that the feeling that you label guilt might be more nuanced. Partly guilt, partly psychological benefits from routines.
It took me a few years to realize that part of my makeup is that I want routine.
Part of that, I think, is I don't want to spend brain cycles trying not to get-away-with things.
YMMV. Good luck.