Does equiping subweapon like dagger adds to your maximum physical attack?
pics if possible
No idea, good question thoe 
Yes, it adds bonus damage to your min/max physical attack. I guess that’s why they don’t have gem sockets?
do you perhaps have screenshot before and after equiping a dagger
i see thank you for the info
side note:
so is it worth it to have low dex and still hit high level mobs (not miss) or the accuracy develops according to your level?
You might have to find what works best for you.