This is a strange take to me. I've been doing .NET for 25 years now. I don't see why you can't just write your code in "Framework 3.5" style in Visual Studio/VSCode 2026 with .NET 10? I would think almost any file from 3.5 would just drop in and compile with practically zero changes. I can't even think of any new language features that are being forced upon the developer.