Yes, it is Win10, so it's supported by default.

The available version downloadable for Windows 10 does not work on Server 2016.

Windows server 2016 is based on Windows 10 so Firefox 116.0 and later should technically run on it. Try the full offline setup in case you were trying to install with the small online stub installer. https://www.mozilla.org/firefox/#product-desktop-release

You could try the Firefox 115.0 ESR (currently at 115.7.0esr) as it supports Windows 7 and later and will be supported until 115.15.0esr in September 2024. https://www.mozilla.org/firefox/all/#product-desktop-esr