Thanks for getting back to me, I appreciate the explanation.

I'm not married to 19.2, I tried using Nuget to retrieve older versions in case that got me out of my predicament, ended up pasting the older version error but my experience was the same across the board, obviously.

It seems like I'm stuck in an institutional/tech bind. My org can't tell me when our client machines will be updated a supported runtime for the nuget packages (currently they're only deploying up to .NET Framework 4.8). Our dev ops team has made it so the build servers have no access to any file system where I could put a copy of the Infragistics binaries, effectively requiring us to use Nuget for our dependencies. Seems like I'm going to need to take this answer to them and explain they have to make an exception for my app.