I have the same thing with any solitary sport. Rowing/Sculling in particular. No phones in the boat (since they're very tippy), and an hour of reasonably delicate physical activity.
The rowing movement requires a little concentration so it absorbs say 40% of the mental activity, what's leftover flows into light thinking and connection-making, without much angst.
https://www.amazon.com/Aqua-Notes-Water-Proof-Note/dp/B01AS5...
Are you able to share your thoughts on how well it worked? I don't trust Amazon reviews.
I've been in this situation. For better or worse, I have a Google smart speaker outside of my shower. On more than one occasion, I have asked Google to remind me to do something the following day and have provided enough detail for me to recollect the thoughts I had in the shower.