The Calculate Accessibility Matrix tool is not included in ArcGIS Pro. You must download the tool from ArcGIS Online (www.arcgis.com/home/item.html?id=23cc1b720eb0418db4d0e61955b8fe43) or GitHub (github.com/Esri/public-transit-tools/tree/master/transit-network-analysis-tools).
Please check out some of the other videos in this playlist for a few ideas. If you have Service Area polygons, you can use the Enrich tool to calculate a wide variety of demographic variables for the area within the polygons. Alternatively, if you’re doing a point-to-point analysis of some sort, you can use census block centroids (or the equivalent for your country) as input for the analysis and then use the data associated with those census divisions.
The Calculate Transit Service Frequency tool is new in ArcGIS Pro 2.9 and is not available in ArcMap. If you want similar functionality in ArcMap, you can download the BetterBusBuffers toolbox from arcg.is/0yr9fr. However, the ArcGIS Pro version of the tool is faster, easier to use, more thoroughly tested, and fully supported by Esri Support. You are highly encouraged to migrate all your ArcMap workflows to ArcGIS Pro.