The people who developed zwave standard understood that there might be times when you need to do an exclusion and you don’t have the original hub anymore. Maybe the hub itself broke, maybe you bought the switch used, whatever.
For this reason, you can issue a Z wave “general exclusion“ from any hub, it doesn’t have to be the one that the switch was previously joined to. So that part is fine.
I will have to leave it to others to talk about exactly how to do the general exclusion as I can’t use the new app.
you might also find the following thread of interest:
V1 Hub Conversion to Aeotec Hub: best practices? {includes discussion of moving in phases}