You say you want to streamline and organise - the only way I can be organised is to do the exact opposite of streamlining!
I have an "essentials" kit, but the only way I can stay organised is to have one of these items per handbag (big bag, laptop bag, small everyday bag x2 as different colours, clutch). I'm well aware this is patently ridiculous but handbags and books are my vices!
Essentials kit (looks a lot but most of these are tiny):
Hair tie
Lipstick
Lip balm
Pen
Mini perfume
Phone charger
Tissues
Painkillers
Antihistamines (horrendous hay fever)
Hand sanitiser
Hand cream (because otherwise I will never ever put it on)
Then phone, keys, AirPods and card wallet are moved with me into whichever bag I'm using. This means whenever a bag is starting to feel cluttered (face wipes, spare nappies that have escaped the changing bag, extra makeup, moisturisers etc) I know I can take out everything barring my essentials kit!
The fact that I own 7 phone chargers (2 for at home and 5 in bags) shows how ridiculous this is for streamlining but it really helps for organisation. And yes I did try to have one kit that I moved around bags but it didn't work for me, I kept forgetting it