This phase II trial tests the addition of venetoclax and/or blinatumomab to usual chemotherapy for treating infants with newly diagnosed acute lymphoblastic leukemia (ALL) with a KMT2A gene rearrangement (KMT2A-rearranged \[R\]) or without a KMT2A gene rearrangement (KMT2A-germline \[G\]). Venetoclax is in a class of medications called B-cell lymphoma-2 (Bcl-2) inhibitors. It may stop the growth of cancer cells by blocking Bcl-2, a protein needed for cancer cell survival. Blinatumomab is a monoclonal antibody that may interfere with the ability of cancer cells to grow and spread. Chemotherapy drugs work in different ways to stop the growth of cancer cells, either by killing the cells, by stopping them from dividing, or by stopping them from spreading. Adding venetoclax and/or blinatumomab to standard chemotherapy may be more effective at treating patients with ALL than standard chemotherapy alone, but it may also cause more side effects. This clinical trial evaluates the safety and effectiveness of adding venetoclax and/or blinatumomab to chemotherapy for the treatment of infants with KMT2A-R or KMT2A-G ALL.