Hi Caroline,
The geoprocessing tools that were included with the Military Tools add-in (pre 2.6) can now be accessed within the Defense Tools toolbox (ArcGIS Pro 2.6 and beyond).
You can access the geoprocessing toolboxes in ArcGIS Pro by selecting Analysis from the ArcGIS Pro top ribbon > Tools > Toolboxes. From here you can search for an individual tool or navigate to the Defense Tools Toolbox.
If you are looking to create a custom group containing all or some of the tools in Military Tools, you can do so by using the Customize Ribbon option within the ArcGIS Pro Options. Instructions on how to do this can be found here.
Let us know if this answers your question, and if more info is needed, please let us know.
Brandon