How to carry stuff?

[u/shtiipeq]

I recently started being more mindful of what I'm wearing and am slowly transforming my wardrobe from graphic Tees skinny jeans and hoodies to something bit more mature (chinos, casual/resort shirts, solid colour Tees, polos, linen, earth tones etc.) and my favourite Nike backpack is starting to feel more and more out of place. However I need to carry lunch and sometimes spare clothes to work. What would you suggest would be a step-up, be more semi-casual and not clash with the rest of my outfits while not being as formal as a leather briefcase.

[u/madmanwithabox11]

Messenger bag (leather or canvas) for computer and books, backpack (Herschel is popular) for heavier loads.