Maybe this tread should be re-named to "Bangkok not nightly anymore next winter"
Itīs easy to understand that AY need to use their prime equipment in a more effective way.
But the key to this is not night flights vs day flights, but the fact that AY only need approx 20 hrs in the air for one rotation, and thus can make one in 24 hrs in total, contrary to most of their competitors.
So this is not an excuse for this ridiculous schedule with the two flights departuring so close to each other, both quite early for the homebounds.

Best would be with HEL departure around 9 pm, you can then have a few hours to enjoy a late dinner and the service, then some nice sleep at a natural time and arrive around noon in BKK.Ļ
Also you could work most of the day even if you are connecting to HEL from most of Europe.
And then the same plane turning back to HEL around 2 pm, plenty of time for connecting flights to BKK then.

The only logic reason I can see for this new schedule is a lack of desired slots in BKK.