Microsoft sadly doesn't prioritize this so this might still be the case for a couple of years.
One thing I credit MS for is that they make it very easy to use modern C# features in .NET Framework. You can easily write new Framework assemblies with a lot of C# 14 features. You can also add a few interfaces and get most of it working (although not optimized by the CLR, e.g. Span). For an example see this project: https://www.nuget.org/packages/PolySharp/
It's also easy to target multiple framework with the same code, so you can write libraries that work in .NET programs and .NET Framework programs.