I'm sure this thread is well and truly dead but figured I'd add my wealth of ignorance;
I roll with an Ortlieb handlebar bag (7L is biggest I can fit) and an Ortlieb Large (I think 14L?) saddle back (attaches to seat post & saddle rails. I add a frame pack if I'm doing gravel touring. I tried rolling without a computer but got a bit stuck when I needed to redo my route and couldn't work Ride With GPS effectively on my iphone. I figured it out but it was a drag. My macbook is too big & heavy so I ended up buying a Surface Go 3 and it's rockin'. Fits in the Ortlieb 7L front bag I put a link to below and lets me carry my cpap up front as well. It's not a super fast machine but works fine for route planning, email, watching video, doing zoom meetings, & almost small enough to use as a kindle to read on . . . it's fine for that but it's a tad big to be my daily driver for kindle books although it works great for that on the bike. I try to load my heavy stuff up front and lighter stuff in back. I roll pretty light for a two week trip. If it would be helpful, I'd be happy to share my packing list which I've sorta refined over the last couple years.
Surface Go 3 (gotta buy the mouse and & keyboard . . . buy an ms arc mouse & the ms keyboard . . . i tried cheaper stuff and it was a drag)
https://www.amazon.com/Microsoft-Sur...s%2C494&sr=8-3
Here's the handlebar bag. I like the mount system. I've got extra mounts on my other bikes so I can move bags or use different Ortlieb backs. The Rix & Kaul ClickFix is a better mount but the ones that come with the Ortlieb are totally serviceable.
https://www.ortlieb.com/en_us/ultima...sibility+F3461
Also, I find these light, reusuable mesh produce bags I buy on amazon to be killer for touring. Great, light weight way to divide up your stuff (tools etc, toiletries, "evening wear", CPAP kit, etc)
https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1