Staycalmsyndrome Enter "windows iso index of" in google and you should find some resources. Might want to try ltsb 2015 first and see if all drivers install correctly. Consider Ventoy for multiple iso's on the same bootable usb flash drive and Strelec's Win PE for troubleshooting.
JTL Sunspark If I remember correctly Rufus downloads the ISO directly from Microsoft servers over a secure connection, so if that's the case it's much safer as well.
KM I wondered how Rufus does it, and it turned out it uses this open source PowerShell script that queries the Microsoft website to offer more download options than you would see when visiting the website manually: https://github.com/pbatard/Fido