Got a typo in a business listing, wrong opening hours, &c.? Sure, you can fix that.
Got a road segment slightly wrong? OK, you can straighten it out.
Any other case where the underlying map data or presentation is wrong? Nope, you can’t report it, and any attempt to report the issue by the channels that are available will fail to have any effect.
And that’s the problem, Maps just doesn’t seem to be interested in providing, y’know, maps. It’s focused on being a business directory instead.
Take https://www.google.com/maps/place/Navarre+VIC+3384,+Australi... as an example: that pin and label on the map is almost 5km south of Navarre, because they seem to have taken the entire suburb area (which in rural areas is regularly many kilometres across) and picked a point on its boundary—I dunno, maybe the furthest point south, maybe just the start position of the polyline—rather than taking a sane point that represents where the town actually is (e.g. its post office) or even a midpoint in the suburb area.
When you look through rural areas you find a substantial fraction of the labels are wrong by several kilometres. Head south to the next town, Landsborough, and it’s marked 4km down the road from where it actually is. I’ve seen some places 10km off the mark.
I’ve attempted to report the Navarre case six or seven times over the last few years while living there, by three different ways (none of which is properly applicable), and it’s still stubbornly in the wrong place.
(Yes, I’m mentioning this here on the off chance that someone relevant will see it and pay attention.)