Genuine Volvo dissy caps and rotors (OEM Bosch) v others.
All I can say on this subject is that I haven't fitted a Volvo part on my 745 since it came off dealership service by my firm in 1996.
I have used Beru (rotors), Febi, Facet and, the 'new' SMP (Intermotor etc) to source replacements (very infrequently). All have provided many years reliable service. I will only choose from these specific badged sources.
At the end of 2023 I replaced a Facet dissy cap and Beru rotor that had been in the car for 20 years. They were in very good condition and didn't really need changing.
Currently, CarParts4Less are running a 24% discount on these items. I always look to see what Arnold Clarke in Glasgow have to offer.
Bob