Is a person afflicted with obsessive-compulsive disorder held accountable for the disbelief that comes to them when thinking about lust or when committing forbidden acts such as masturbation, and is it necessary for him to renew the marriage contract if his seclusion with his wife is considered consummation?

The treatment for these intrusive thoughts is to ignore them, seek Allah's help, make supplications (du'a), and consult trusted doctors, based on the hadith (definition): "Seek treatment, for Allah Almighty has not created a disease without also creating a cure for it."

Everything you mentioned about the shape of your fingers, that it mocks Allah, or the prohibition of your wife, or knowing everything that comes out of you, are symptoms of severe obsessive thoughts. There is no need to pursue these assumptions; live your life normally.