I can say that's not been my experience but I've never seen 50 nuget packages in a single project. It doesn't necessarily surprise me that it becomes painful after 50 but what in the world were those 50 packages for?
So you don't have to add a dependency to a project just because another dependency has a dependency on it. It might allow you to start removing dependencies.
I've been told packages.config allows pre/post events that PackageReference doesn't so it may be that it's not an option for you, but even then I'd try really hard to move away from packages.config.
You probably know this already, but just in case;
I would also strongly recommend not using packages.config or upgrading if you can. PackageReference can deal with transitive dependencies because the compiler resolves them for you: https://learn.microsoft.com/en-us/nuget/consume-packages/pac...
So you don't have to add a dependency to a project just because another dependency has a dependency on it. It might allow you to start removing dependencies.
I've been told packages.config allows pre/post events that PackageReference doesn't so it may be that it's not an option for you, but even then I'd try really hard to move away from packages.config.
Here's some migration documentation just in case: https://learn.microsoft.com/en-us/nuget/consume-packages/mig...