Researchers are looking for new ways to treat locally advanced or metastatic urothelial cancer (UC). Current treatments for locally advanced or metastatic UC include chemotherapy, immunotherapy, and targeted therapy. Researchers want to know if giving sacituzumab tirumotecan (sac-TMT), the trial medicine, can treat locally advanced or metastatic UC that got worse after certain treatments. The goal of this trial is to learn if people who receive sac-TMT live longer than those who receive certain non-platinum chemotherapies.