Thanks for linking this. I wasn't surprised Microsoft made their AI auto completion proprietary (they did similar for C# in VSCode). But it grated me that semantic highlighting wasn't open source.
You can use an extension fork which swaps it with NetCoreDbg maintained by Samsung instead. This is what VSCodium uses.
Also note that both of these essentially consume the debugger API exposed by the runtime itself, you can easily make one yourself in a weekend but no one bothered because there isn't much need for another one.