I have been surprised how easy it was to get my not-too-technically-savvy mum to use Manjaro. She spends the vast majority (if not all) of her time in the browser, so there's no difference.
I wouldn't have gone for Manjaro, but Linux environments with user friendly interfaces are great for many more people than they would appear to be at first glance.
You'll need to play tech support every now and then ("I have a new printer, and...") and you'll need to teach people the basics, but a lot of occasional computer users will be happy with modern Linux.
However, if you use your computer for your job, you'll either have an interest in learning how to accomplish it, or you'll have an awful time using Linux. Microsoft Office still has an edge over any open source product out there. Games work (sort of) through Steam, but if your games come from Epic you'll need to dive into the world of alternative launchers and compatibility layers to play them (if they even work at all). VPN/RDP software can usually work, if you put in the effort to learn about how they work under the hood and what configuration files you need to edit.
This leads to a pretty wacky parabolic usability graph, where Linux is great for the people with the least amount of interest and knowledge about computers and for computer experts, but bad to unusable for those in the middle between the two.
Desktop Linux has been bridging the gap, with more and better GUIs and better defaults, but as long as we'll have loud, hardcore "everybody needs to know the terminal or they shouldn't use Linux at all" Linux users I'm afraid ChromeOS will eat Linux's lunch before anyone even notices.
She’s since died, but my grandmother ran a minimal Linux distro I installed for her (I think lubuntu) for years and I think in 6 years or so had only one issue that needed help (someone to read the error message and okay the fsck).
Otherwise, I doubt she noticed the difference from her prior Windows usage.
