This is a topic of concern because (after Googling) many Linux users would like to get what they pay for vis-a-vis streaming services in Linux. I want 1080 dpi. I've tested many extensions in the past two years and most do not work. These work for me. YMMV.
Problem: Linux won't stream in 1080 dpi from top tier online services.
Solution for Netflix in Chrome or Edge: Install Netflix - higher quality - Chrome Web Store
Solution for HBOMax in Chrome or Edge: Install HBO GO Quality Enforcer - Chrome Web Store
For Firefox, I've only found for Netflix: Netflix 1080p – Get this Extension for 🦊 Firefox (en-US)
I will keep searching.