Well it’s easy to understand why legislatures elected by a Gerrymandered map are not motivated to fix it.

Also not trivial to design a law against it. Most common solution seems to be use of independent commissions, but commissions can also be “independent” in name only.

an independent and officially non-partisan commission is imperfect, but will at least have constraints on it in that it needs to appear independent, unlike the brazenly partisan way things work now.

Are State elections also badly affected by gerrymandering?

I have only ever seen examples of it at the Federal Election level, so wondering if your first point is actually completely accurate. (I believe the States themselves control the "maps" but forgive my ignorance if not)

The states control both maps, the district map which determines the population eligible to elect the US Rep for a given district, and a separate district map (with more and smaller districts) that determines the population eligible to elect the State Rep for a given district.

Both are a problem. The latter just means that the State Congress can be artificially heavily tilted vs one party or the other.

It's not at all astonishing, since those who write the laws benefit from the gerrymandering. Even if a legislature passed a law forbidding gerrymandering, future legislatures could reverse it. If the party in control of the legislature is corrupt, then that is exactly what we should expect.

Gerrymandering should be prohibited by the courts, but the current SCOTUS in its great wisdom ruled that courts must remain silent on the subject.