How to Advance in Your Programmatic Ads Career

Hello everyone! I've been working in the digital marketing field for the past 8 years. For the last 3 years, I've been with the same agency, focusing solely on Amazon DSP. My colleague and I make up the entire team, handling everything related to Amazon DSP except for custom creatives. I'm not based in the US, and my annual salary is approximately $48,000. While this is considered a good income in my country, I feel limited by my exclusive experience with Amazon DSP. Most companies prefer candidates with comprehensive PPC knowledge where Amazon DSP is only a bonus, or they look for expertise in programmatic advertising with platforms like Google or The Trade Desk (TTD), rendering Amazon DSP experience as secondary. I'm seeking advice on how to expand my skill set to increase my earning potential. Where would you suggest I focus my efforts?