There are a large number of online chat spaces devoted to PostGIS topics.
The Matrix federated chat network includes a #postgis:osgeo.org channel for PostGIS discussion. Choose a matrix client and start chatting.
There are a number of Slack communities that include PostGIS channels.
PostGIS channel on “PostgreSQL, People & Data” server. There is also a “GIS” server but no specific “PostGIS” channel there so far.
#postgis channel on the Libera.chat network. Install an IRC client or use the web client.