JetBrains Rider is available for Windows, Linux, and macOS, and it's much better than VS, VS for Mac, and VSCode.

It's not free, but VS isn't either for any serious commercial usage, and Rider is certainly worth the money.

What does the company that owns Java offer? Their Java IDE is https://en.wikipedia.org/wiki/JDeveloper and nobody uses that. The latest release came out in 2019. Everyone is using IntelliJ IDEA or perhaps Eclipse.

What does the Python core community offer? IDLE is ugly, is barely an IDE, and didn’t have line numbers until a few years ago. Everyone is using PyCharm or VSCode.

IBM also makes Java, it offers Eclipse.

Sun made Java, it offered Netbeans.

As for the Python community, no one expects great tooling from FOSS languages, as you mention everyone is using tooling from two big corporations.

NetBeans is also still going, although I don't think it has many users.

Does Java even have a MAUI equivalent? There are other open source frameworks for GUI apps. This feels like goal post shifting.

The point is cross-platformness and windows does have MAUI, so not having it on linux means it is not a first-class target.

MAUI is just another workload of the dotnet ecosystem. There is no technical reason for it not to work on Linux outside of someone actually doing so. This has nothing to do with C# at all.