Support for S-57 is in the product plan, though not immediately in the next release (2.8). See https://community.esri.com/t5/arcgis-pro-ideas/enc-s-57/idi-p/968679 up vote/follow for updates.
As for the question about C-Map, is that referring to https://commercialmarine.c-map.com/en/route-planning-and-fleet-management/c-map-fleetmanager ? Maybe somebody in the https://community.esri.com/t5/arcgis-maritime/ct-p/arcgis-maritime place has more insight, but whether/when they develop a solution for ArcGIS Pro may be a better for C-Map directly.
I hope you are doing well.
In the past, C-MAP only provided their propriety C-98 formatted ENC datasets that required a plugin for ArcMap. Now we have ArcGIS Maritime Server Extension (Maritime Chart Service MCS) customers using C-MAP data. MCS only supports standard S-57/S-63 datasets, so C-MAP must be providing that option now. If your customer requires the use of S-63 encrypted datasets, they will still be required to use MCS to publish map services and bring those into ArcGIS Pro.