I'm having the same issue, but on Linux (RHEL 9).
From my research, the problem is not MathLink but it can't find the .NET runtime.
On my RHEL 9 system, I've got .NET 8.0.4 (/usr/lib64/dotnet), but I think MathLink is having trouble finding it or it may be an incompatible version with MM v14.0, However, I can't find any documentation on .NET version requirements for Mathematica.
I'm assuming you are on Windows? Did you get this figured out?
