Upgrade plugin version 4.2 to version 4.4

Hello good time
I have a plugin source that works properly on version 4.2 when I build and place it in the plugins folder.
But I want to use this plugin in version 4.4, so I made two changes, one in the plugin file, I changed the version to 4.4, and the other, I edited the solution or plugin file for <TargetFramework> net5.0 </TargetFramework> and then I built it in the place of plugins and after restarting the application, the plugin will be in the list, but the problem is that it is no longer in the list after installing the plugin, and if I restart the application with the error "HTTP Error 500.30 - ASP.NET Core app failed to start "I encounter?!? Does anyone know why?

There are a lot of infrastructure changes between v4.2 and v4.4
Depending on what the plugin does and if it does anything much at all then veritually every routine needs to be modified
Best to compare one of the standard plugins between the two versions using a Diff tool and see the types of changes that need to be made