What changed is that I noticed how, left to my own devices without external schedule pressure, I would naturally drift 3h forward every day - and so I realized I had the opportunity to actually fully go with the schedule my body seemed to want to have. I informed my family what I intended to do, cleared my calendar for the next week, and went for it.
First observation: my biggest hesitation was social judgement. I was consciously aware of how little I wanted people to think I was a weird dude.
Well, turns out I'd rather be weird and feel great than normal and feel like a zombie. My body almost immediately seemed to breathe a sigh of relief and six months later, this part of my life is amazing.
I find it endlessly curious how some people seem seriously distraught when I tell them what I've been up to. Not because they have any medical opinion, but because it appears to challenge something that clearly gives them a feeling of being normal.
My doctor actually had very little to say, once they heard me out and read the research I gave them. Essentially, "please stop if you start feeling bad".