nonnegotiablenili's journey

I'm currently working in Brazil for a global business unit, where my direct managers are based in the US. I'm expected to go into the office once a week, but I've only been managing to go about once a month. Recently, I found out that the only other person in my Marketing department in Brazil left the company, which means I'm now solely responsible for all Marketing operations here, including managing a significant media budget. I'm moving to a different state soon, and I really want to stay with the company, so I've been considering asking my manager if I can work fully remote. I have a performance review coming up on Monday, and I think this could be a good opportunity to discuss my situation. The company recently did a risk assessment and concluded that losing me would severely impact the Marketing operations in Brazil, which gives me some leverage. However, I'm unsure how to approach this conversation. I've typically been passive in negotiations, focusing more on my work than on advocating for myself. With the bureaucracy in Brazil, I know I need to present my case clearly so my manager can negotiate with HR effectively. I’m aware that other teams have flexible arrangements, so I believe it's possible. I have several reasons for wanting to work remotely, including the fact that I'm the only one handling Marketing here, the office environment isn't conducive to my needs, and my current salary is below market rate for my new city. I want to make a compelling business case without overwhelming my manager with personal details. I feel like I need to strike a balance between my personal circumstances and the business needs of the company. I hope to gather some advice on how to best frame this conversation on Monday.