Study of GS-3242 in Participants With HIV-1; Substudy-05

Key Inclusion Criteria: All Substudies: * Plasma human immunodeficiency virus-1 (HIV-1) ribonucleic acid (RNA) ≥ 5000 copies/mL but ≤ 400,000 copies/mL at screening. * Cluster of differentiation 4 (CD4) cell count \> 200 cells/mm\^3 at screening. * Antiretroviral (ARV) treatment-naive or treatment-experienced but naive to the investigational ARV drug class being investigated in the given substudy and have not received any ARV within 12 weeks of screening, including medications received for pre-exposure prophylaxis (PrEP) or postexposure prophylaxis (PEP) (note that current or prior receipt of long acting (LA) parenteral ARVs such as monoclonal antibodies (mAbs) targeting HIV-1, injectable cabotegravir (CAB), injectable rilpivirine (RPV) or injectable Lenacapavir (LEN) is exclusionary). * Have adequate renal function (estimated glomerular filtration rate (eGFR) ≥ 70 mL/min/1.73 m\^2) * No clinically significant abnormalities in electrocardiogram (ECG) at screening. Substudy-05: * Willing to initiate BVY provided by the sponsor, or an alternative SOC ART regimen selected by the investigator on Day 11 or upon ET. * Participants must also be willing to comply with meal requirements on dosing days. Key Exclusion Criteria: All Substudies: * Known historical genotypic or phenotypic resistance to 4 major ARV classes (nucleoside reverse transcriptase inhibitor (NRTI), nonnucleoside reverse transcriptase inhibitor (NNRTI), protease inhibitor (PI), integrase strand-transfer inhib…