I've owned the same model Rollei you just bought
for 30 years. I use it fairly regularly. I suspect the slower shutter speeds are a bit slow, and the shutter release is a bit slow closing the shutter on "B." It's time for a clean,lube, adjust. I will never sell this camera.
Finding accessories is a bit of a hunt, but it's fun. You'll begin to recognize the brown leather cases for the filters, lens hood, closeup lenses and other accessories when they pop up on used camera sites or in old camera stores. Expect to pay good money for them, they're worth it!