Forget the binary of high or low season; the question is not there for real budget optimization.
The real lever is anticipation and flexibility regarding the exact reservation date, not the season itself as a rigid category.
A coastal accommodation booked six months in advance during summer can be cheaper than a last-minute low season stay, for example.
You need to play with exact dates, even within a season, to find the best deal.
Don’t be guided by the menu of seasons, but rather look for the third way of off-peak dates.