Okay so it looks like Explorer is not technically dead on windows:
Deprecation Notice for Explorer, Collector, and Tracker (esri.com)
"What about the Windows versions of Collector and Explorer? Will they be retired in December 2021 as well?
We are not actively in development of ArcGIS Field Maps on the Windows 10 platform, so Collector (Windows) and Explorer (Windows) will be supported for the foreseeable future. While they are not planned to retire – there are no additional enhancements planned for the Windows apps.
For users who need a Windows solution in active development, ArcGIS Survey123 and ArcGIS QuickCapture are active in their cross-platform development and continue to build new features on the Windows platform.
Additionally, ArcGIS Pro supports GPS-based data collection workflows (blue dot, map panning to keep blue dot centered, etc.). ArcGIS Pro already supports commonly requested features such as the Utility Network and the ability to operate completely offline for long periods of time."
So, this does not say anything about windows 11 support. I am guessing it is not supported there.