topology.PointOnSurface(TopoGeometry)

[strk]

To do the ST_PointOnSurface() operation without the need for a cast to Geometry.

I would not use an ST_ prefixed functions because that prefix under topology is used to distinguish ISO SQL/MM specified signatures from the others, and SQL/MM does NOT know about TopoGeometry at all.

But we could be nice and use the ST prefix like we actually already do with ST_Simplify(TopoGeometry) - ​https://postgis.net/docs/TP_ST_Simplify.html

See also #4861 which would likely be a basic component of this, for Areal TopoGeometry objects