You can stay as long as you USCIS do not make decision on the case, having said that it is better to leave before the expiry of the visa unless circumstances is beyond your control (which is valid during COVID). But be ready to explain at POE when they try to come back in future. Keep all the extension request letter and approve denial letter. Staying more months in a year in US than home country may jeopardize future visa applications and subject to cancellation of visas if you do not provide valid reason for your extended stay. You don't want to show immigrant intent.