Hi there!
When it comes to Pixel Streaming at scale, you are right in that in can get expensive quickly, especially if your available instances are always running.
The best option if you’re looking to incorporate Pixel Streaming at scale is to look into third party options. There are a number of teams who have made scalable Pixel Streaming platforms that streamline the process.
I can’t actively recommend any specific option, but I do recommend having a look into what’s available!