OK Guys, yes I know this comes up every year…well at least for me it does.
So after I think I got the But Splat thing solved? When I re-installed 2025 Version 25.0.0.571 64 Bit? No matter how many times I install the driver 3DxWare64_10-9_b671 from 3D Connexion? It will not load into the 2025 SU.
I open the extension manager and the extension is not there. See below:

image1256×837 67 KB
It is alive and well in my 2024 SU as shown below:

image1252×838 64.5 KB
Not panicking as this happens every yearly upgrade but it would be nice if somehow we could find a .rbz file to just load in?
Oh well any suggestions lease let me know what worked for you and I will run through the process…