Okay everyone! So, Leo, sorry for accusing DOpus as the issue. It seems the culprit is a Microsoft update KB5050094. I seemed to also have issues dragging items in Adobe Indesign, and started searching. I found a random post here that talked about Premiere not dragging dropping on second screens, and it also mentioned the mismatch scaling. Uninstall it, and boom, everything works again. Here is the MS post about this optional patch.
So at least this part isn't a DOpus issue, but affects many things on second screen, and maybe this post can help anyone else having issues.
Thanks, Leo and your team for an awesome piece of software. I use it daily and you can see how this bug was affecting my workflow! Have a great week!