> moderately strenuous exercise like riding a bicycle destroys my sleep quality for several days.

this is surprising! Not that this would be easy to just do, but have you ever leaned into it for a while (like a month) and seen if that persists? I'm obviously not a doctor or anything -- I just wondered in reading that whether it may possibly be a change shock that would subside after a brief period at a higher activity level, resulting in the best of both worlds.