Update - I successfully fixed this issue via Taxpayer Advocacy team - https://www.taxpayeradvocate.irs.gov/notices/notice-cp12/ or call [phone number removed]
After a grueling 5-6 hours of irritating answers, hang-ups, full calling queues, and more - I finally got the answer which ultimately was my main request. After stepping through each line item of the Recovery Rebate Credit form, the Tax Advocacy agent acknowledged a mistake was made and fixed the issue on their side. I'll receive the remainder of my expected return in a few weeks!
