A Study of JNJ-79635322 in Participants With Relapsed or Refractory Multiple Myeloma or Previously Treated Amyloid Light-chain (AL) Amyloidosis

Inclusion Criteria: For participants with relapsed or refractory multiple myeloma: * Have a documented initial diagnosis of multiple myeloma according to International Myeloma Working Group (IMWG) diagnostic criteria * Part 1: Have relapsed or refractory disease, have been treated with a proteasome inhibitor, immunomodulatory drug (IMiD) agent, and an anti-CD38-based therapy for the treatment of multiple myeloma (MM),and should have been treated with at least 3 prior lines of therapy, or are refractory to proteosome inhibitor, IMiD agent, and an anti-CD38-based therapy regardless of prior lines of therapy, Part 2: Have relapsed or refractory disease, have been treated with a PI, IMiD and an anti-CD38 based therapy * Must have an Eastern Cooperative Oncology Group (ECOG) status of 0 or 1 * Have measurable disease at screening as defined by at least 1 of the following: a) Serum M-protein level greater than or equal to (\>=) 0.5 grams per deciliter (g/dL); or b) Urine M-protein level \>=200 milligrams (mg)/24 hours; or c) Light chain multiple myeloma: Serum immunoglobulin (Ig) free light chain (FLC) \>=10 milligrams per deciliter (mg/dL) and abnormal serum Ig kappa lambda FLC ratio; d) For participants without measurable disease in the serum, urine, or involved FLC, presence of 1 or more focus of extramedullary disease (EMD) which meets the following criteria: extramedullary plasmacytoma not contiguous with a bone lesion, at least 1 lesion \>=2 centimeter \[cm\] (at its greate…