Have you ever considered the Linux OS
Most of the people I know, use Windows OS. A few will use the Mac OS. However, very few use Linux. I do, although I admit I dual-boot Windows and Linux.
While this is for 2018, I think the information is fairly accurate.
It mentions for light distros, Lubuntu. I have that on one of my used Laptops, and it runs rather well. It has a look and feel of Windows, and if you already have Windows on your HD, and don't want to have a lot of space for it, it can be sufficient to cover your needs. There's a Tiny Linux, and "Damn Small," but those versions, IMO, are only if you really know your way around Linux, and know how to work the system. Most of your distros have the ability for you to download the software right from their repositories through a GUI. Sometimes, you may have to go into the terminal (their version of DOS), but mostly, the GUI software repository suffices.
While they suggest Elementary OS, I haven't found it to my liking, and so use Mint. Like Lubuntu, it looks much like Windows, and is fairly easy to navigate. It's also one of the most used distros, with lots of community support, so if you have problems, there is a good chance someone can help you figure out the problem. I should note that I've played with Ubuntu, and it is decent, as well, and the most used, personal distro. The layout is more like a Mac, than Windows, however.
For privacy advocates, Liberty Linux was good, but is no longer being developed. I've heard good things about Whonix, but I haven't tried it. Older versions of tails, like 1.x, worked well. The 2.x versions had some good, and some not so good, and buggy. Version 3.x, the last I've used, seems to have corrected the buggy issues. I've had problems with persistent drives, as well as encrypting chat, like OTR/Pidgit. I for persistent drives, I've opted to simply use external flash drives that I've encrypted. I tried Ipredia, but couldn't get it to really "do anything," so can't, currently, recommend it.