Recommend me a pannier backpack please

[Sewbean]

Can anyone recommend a decent pannier bag that can be used as a backpack?
I need it to be waterproof and big enough to fit a laptop, change of clothes and my lunch.
I’m not planning on using it as a backpack for hours on end but to get from the bike shed into the office, or when I stop off at the supermarket.
Our local bike shop doesn’t have any and it’s tricky to get a feeling for how they work looking online. Lots of them look like the pannier clip will dig into your shoulders even just in 5 or 10 minutes.

Any recommendations gratefully received

For the light use you need, can't you just have it on your shoulder with long strap? That's what we do. Any bag like this you could clip a luggage strap to would work.

Alturas have been good for us.

How about this?
www.albanbikebags.com/tote-pannier-bicycle-bag-black-and-black-270.html

I've always found carrying panniers a PITA, even the ones with a shoulder strap, as the bottom tends to swing in and bash your legs. So I'd go the other way, and get a basket on the back of the bike to put a decent rucksack in, then bungee over the top for security.

You can get Ortlieb brand pannier backpacks. They're probably the best, waterproof and pretty bombproof. They're not stylish and they are relatively expensive but they'll last for years.
www.ortlieb.com/us/vario