To give an accurate assessment of whether Adele was overtraining or not we would really need to know more about her routines, diet and recovery methods.
It's also worth remembering that she done a lot of this training during lockdown (as far as I'm aware) so likely had time to eat and rest properly.
There are also many athletes who train twice per day 5-6 days per week, so it can be done if managed correctly.
However, I do agree with you that for the rest of us 'normals' lol, training 2-3 times per day can cause some serious issues and is likely not required for the majority of health and fitness goals.
I would love to have the time and money to train twice per day, just to see the results it produced for me.
Anyway, thanks for sharing this piece, I enjoyed the read 😁.