Hello @castavernas and welcome to the NVIDIA developer forums.
Yes the plug-in will be updated for UE 5.3.
the difficulty here is that we can only start the update progress as soon as Epic releases the official version and we get access to sources to build the plug-in against.
And then we need to go through a thorough QA process to be sure we do not introduce any regression with the update.
As developers yourselves you will understand that such a process takes time. And sometimes more than we are hoping for ourselves.
So for now I can only ask kindly for your patience and to watch out for an announcement here and on the DLSS pages.