Higher or Lower Dose Cladribine, Cytarabine, and Mitoxantrone in Treating Medically Less Fit Patients With Newly Diagnosed Acute Myeloid Leukemia or Myeloid Neoplasm

Inclusion Criteria: * Diagnosis of untreated "high-grade" myeloid neoplasm (\>= 10% myeloid blasts by morphology in bone marrow and/or peripheral blood) or AML other than acute promyelocytic leukemia (APL) with t(15;17)(q22;q12) or variants according to the 2016 World Health Organization (WHO) classification; patients with acute leukemias of ambiguous lineage are eligible; outside diagnostic material is acceptable as long as peripheral blood and/or bone marrow slides are reviewed at the study institution and cytogenetic/molecular information is available * Treatment-related mortality (TRM) score \>= 13.1 as calculated with simplified model * The use of hydroxyurea before enrollment is permitted; hydroxyurea should be discontinued prior to start of study treatment. Patients with symptoms/signs of leukostasis, white blood cell (WBC) \> 100,000/uL, or acute symptoms felt related to their high-grade myeloid neoplasm can be treated with leukapheresis or may receive up to 1 dose of cytarabine (up to 500 mg/m\^2) anytime prior to study day 1 * Patients may have received treatment (e.g. azacitidine/decitabine, lenalidomide, growth factors) for antecedent low-grade myeloid neoplasm * Left ventricular ejection fraction (LVEF) \>= 45%, assessed within 3 months prior to registration, e.g. by multigated acquisition (MUGA) scan or echocardiography, or other appropriate diagnostic modality * Women of childbearing potential and men must agree to use adequate contraception beginning at the s…