Can you please let me know AGOL or Portal can consume feature/map services which are not ESRI hosted for example geoserver WFS/WMS. If so then how? Or in order for AGOL/Portal, service should be hosted by them only.
You can add both WFS and WMS services to view them in both the ArcGIS Online and Portal for ArcGIS map viewers.
Add layers—ArcGIS Online Help | ArcGIS
Hope this helps,
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