I've been using Airs as my primary machine since 2010. I don't use bulky software (XCode, Adobe suite, Office, etc), so if you use any of that I wouldn't recommend it, but for software dev it's been plenty fast and a real joy to use.
The only time I'm speed constrained is deep learning, but generally I just run tiny test sets locally and then run full jobs on a cluster or the cloud.
In the mid 2010's I had a desktop with like 64GB of Ram and four million processors, and I found programming on the Air I was still more productive. Productivity wise I think it's a very high dimensional space to consider.
There's a noticeable latency using gmail.com on my iMac Pro, too.
I've always used powerful desktops (Mac Pro, iMac Pro) and MacBook Airs while traveling, and while the Airs aren't very good for video games like StarCraft II, I've never had a problem with performance while doing anything else (I work in VS Code on TypeScript). My unit tests run in ~20 seconds on the MacBook Air as well as the iMac Pro.
Since the new MacBook Air doesn’t have a fan while the MacBook Pro does, I’m sure there are some differences that Apple isn’t admitting right now. The battery life claimed by Apple is also higher on the Air compared to the Pro. Maybe the Air is throttled or runs at lower clock speeds.
If you configured them the same (chose the more expensive Air), the Air and the 13" Pro have the exact same specs from what I can tell other than a slightly brighter screen (500 nits vs. 400 nits) and slightly bigger battery (58.2 whr vs. 49.9 whr) on the 13" Pro.
the air is really sluggish for anything but the lightest of tasks. there was even extremely noticeable latency using gmail.com