Messenger Bag as photo bag

I've had a messenger bag as my photography bag for most of my amateiur photographer career for the past 15 years. They are stylish and I fit everything in.But now I feel when I have it on my the whole day my neck afterwards hurt a lot on the one side, like really a lot.I mostly take my camera with me when we go travel with the family, we have two children and I have to carry the little one constantly.This leads to me sometimes not to bring my camera because it's just to hurtful. And then I regret it every time I look at the phone pictures.

I guess it's time for a travel camera backpack ...

Edit: I have a lot of things to carry, the Sony A7C body, a 35mm f1.8, a 70-200 f4, and a small cheap pancake lens. Then strong usb-c charger which I use for charging phone, camera and laptop. Sometimes I bring the laptop also.