How to ask for a raise

I have 4 years of working experience (3 in sales and 1 as an associate product manager), all at the same company. I took a big pay cut to move to Product because it was an entry level Product role, which I was ok with at the time because I wanted to work in Product and saw it as my opportunity to break in. However, I am still being paid ~10k less than an average APM in my city based on my research on Glassdoor, Payscale, etc. Career progression here is not straightforward due to a lot of turnover in middle and upper management (have had 3 managers and 2 directors in a year). I was promised by the manager that hired me that I would be “fast tracked” to a PM role within a year. I’m not naive enough to consider that a binding agreement considering it wasnt in writing and he left the company a few months later. It’s still frustrating because I am now doing PM work and being paid less than the average APM. Career progression talks with my manager have gone nowhere, although he is a busy guy and I haven’t pushed the issue too hard, which is on me. My question is how would you guys approach this situation / frame the conversation with my manager? Is it good practice to mention average salaries in my area, or should I focus on my personal achievements and let them speak for themselves? Have never been in this situation before (could make more money in sales by closing more deals) so I’m not sure how to move forward. Should I just leave the company? We’re 2-3 quarters out from an IPO which has made me hesitant to leave. TC: 65k