dynamic feature in .NETTIL that dynamic is now an “Archived Component” of the framework.
It is not evolving and receives only bugfixes or maintenance changes.
System.Linq.Expression is "archived component". dynamic as it exist today is effectively deprecated tech. It is not good for new tech to take dependency on effectively deprecated tech.
I wanted to use dynamic with System.Text.Json but apparently it is discouraged.
See this GitHub issue