I've seen multiple people claim it works for Windows ISOs and multiple people claim it doesn't work - mostly right here on this site!
I love Etcher. It works great... (most of the time)... with Linux ISO files.
I think I'm one of those who say it won't work with Windows 10, and I'm afraid I have to stick with that story. I just downloaded the latest appimage (1.5.115-x64) from etcher.io website and it still fails me. The GitHub site instructions for adding a repository for Debian/Ubuntu also fails with errors on my Ubuntu-based Zorin, and I'm not interested in trying to fix this. I also have no interest in building it from source, but the source is slightly newer (1.5.121) than the appimage on etcher.io. Burning a Windows USB is just not worth all this trouble.
I have the latest ISO downloaded from Microsoft, Win10_21H1_English_x64.iso, and Windows Media Creation Tool successfully burned this to a USB. I've used that USB for 2 successful installs on laptops recently. So there is no defect in the ISO. If Etcher needs to be run inside Windows in order to burn a Windows ISO, then you might as well use Media Creation Tool instead. If you can get Etcher in Linux to actually work to burn a working Windows 10 ISO, then please enlighten me. Again, though, Etcher should be a "simple solution" and not require building from source.
Wanna try for yourself? You can download Windows 10 from Microsoft
here. It's about 5.4 GB. I suspect that the Windows ISO is not a standard ISO, and that is causing the problem. I have not found any Linux tools that will work correctly, though there are several who claim to work. I am tired of trying... Windows is not worth all this trouble. (Be careful, or I'll say that again!

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Etcher fails at the first stage... picking the ISO file. Here is what it shows: