Hey AJ - I was able to resolve the problem by using an assembly redirection. Looks like in V12 SP4, Aras Innovator already uses an ApplicationInsights.dll, v2.10.0. This conflicts with the version 2.3.0 included in this project. When attempting to upgrade from 2.3.0 -> 2.10.0 in this plugin project, there's a level deeper version mismatch on System.Diagnostics.DiagnosticSource.dll which I was not able to resolve. This is actually why I used version as 2.3.0 in the first place, because 2.3.0 does not have any reference to this DLL at all.
You can resolve this by making the references to 2.10.0 point to 2.3.0 by editing the Innovator/Server/web.config file, and adding the following redirection (you can add it in with the other redirections)
<configuration>
<runtime>
<assemblyBinding xmlns="urn:schemas-microsoft-com:asm.v1">
<dependentAssembly>
<assemblyIdentity name="Microsoft.ApplicationInsights" publicKeyToken="31bf3856ad364e35" culture="neutral" />
<bindingRedirect oldVersion="0.0.0.0-2.10.0.0" newVersion="2.3.0.0" />
</dependentAssembly>
</assemblyBinding>
</runtime>
</configuration>
Please try and let me know if this works for you.