UnicodeJsonConverter is the wrong way to encode strings with System.Text.Json

[rjgotten]

System.Text.Json supports encoding schemes using the JavaScriptEncoder class directly via its serializer options.
https://learn.microsoft.com/en-us/dotnet/standard/serialization/system-text-json/character-encoding

Using a converter for this is an anti-pattern and might double up on the time spent on escaping.