Hmm... It looks like this is a spin-off to the " https://mangadex.org/title/52893/forced-to-become-the-villainous-son-in-law ". It looks like this is the part of the main story that covers the arc with the third heroine which comes in the future of the main story. So, a sequel spin-off? Someone should add this as the related series to the main story. @Willie29
@SUBARU Well most stories like this the MC do and act in a somewhat similar way for mostly the same reason. not to mention between the stories there are thousands of year in-between.
My only peve is you got these characters aging like a kid whishing to be taller on their B-day and it comes true