The purpose of this study is to evaluate an investigational drug called ubamatamab in patients who have advanced ovarian cancer. Researchers want to determine how safe, tolerable, and effective ubamatamab is on its own and in combination with other anti-cancer drugs (bevacizumab, cemiplimab, fianlimab, and a standard chemotherapy drug, pegylated liposomal doxorubicin). The study will also examine the side effects of the study drug and its experimental combinations, as well as whether the body makes antibodies against ubamatamab (which could make the drug less effective or could lead to side effects) and its combinations. Participants will also receive another investigational drug, sarilumab, that is intended to help reduce side effects that may occur when taking ubamatamab. Ubamatamab is a type of medicine called a "bi-specific antibody." Antibodies are proteins that bodies naturally make to fight germs, but scientists can also create them in labs to help treat diseases like cancer. Ubamatamab aims to help T-cells find and destroy ovarian cancer cells.