How to uninstall roon 1.8 completely before reinstalling it? I cannot add audio zones and and I find no way to add a new device

the libraries and databases are found in a different location of different systems

you may find just renaming the RAATServer folder with old on the end a better first shot than removing everything. worst case rename the roon folder to Roon.old

I’m not sure what mean its considered as a core, if its not authorised it should be fine, and core also runs bridge so it should be seen as an endpoint. If you remove roon it wont show up at all unless maybe you install Roon Bridge on it.

perhaps you seek help from the manufactures support folks first

perhaps more info on the PS2 dac of which im not sure who makes it