"I think there is a physical aspect because chess exhausts a lot of energy, especially when games last 6-7 hours, and here women could be more disadvantaged."
Why deny differences in biology to further a false reality?
https://www.chess.com/article/view/hou-yifan-interview-chess
It is unclear why, this requires further research - the Chess world decided to just roll with it and have separate tournaments.
There is research from 2007 ( https://onlinelibrary.wiley.com/doi/epdf/10.1002/ejsp.440 ) which shows that if is via Internet and women thinks their opponent are men - they show worse results. If gender is not known to both sides - results are mostly same.
It's not currently clear if M2F transgenders should be allowed to play in women competitions.
> It was the last Olympic skeet competition open to both men and women, and the only mixed shooting competition at the Olympics ever won by a woman: Zhang Shan.
For non physically demanding sports most of the work is in training prior to this competition: being able to find good coach, stick to regime, balance life vs sport, emotional control, managing finances and sponsorships, chances of getting into the sport in the first place etc. These aspects are quite different for men and women, so they naturally have separated tournaments.