I don't think whoop influenced my rhythm that much. But I had quite a steady rhythm already, so it wasn't too much of a problem. I think I mostly profited from whoop by having an assessment for my quality of sleep. This made it much easier for me to decide how to prioritize my work, e.g. when I should do intellectually intense stuff and when light work.
I haven't tried any of your other suggestions, e.g. CBT, so I cannot comment on them. But thank you for sharing your experiences.
Thank you for the valuable feedback. I'll try to improve that more in future posts and add more paragraphs here.