AtlasOS is described as 'An open and transparent modification of the Windows operating system, designed to optimize performance and latency.
AtlasOS is creating a "kinder" Windows experience. Reducing bloatware and optimizing performance for enthusiasts, gamers, and privacy-conscious individuals' and is a operating system in the os & utilities category. There are more than 10 alternatives to AtlasOS for a variety of platforms, including Linux, Windows, Mac, Wine and Steam apps. The best AtlasOS alternative is Pop!_OS, which is both free and Open Source. Other great apps like AtlasOS are SteamOS, Windows 11, Nobara Linux and Revision (ReviOS).
Pop!_OS is a good Linux distro but it isn't a modified version of Windows which AtlasOS