I'm editing a feature being shot on an Arri Alexa Mini with a ProRes 4444 file codec at 2944x2160 resolution image. Though editing on ProRes 422, I'm keeping the native resolution in offline and we'll be onlining back to the original ProRes 4444 camera footage when we finish. I am editing in Avid Media Composer 2018.12.01.
What is the maximum I would want to digital zoom or push in on an image in Avid MC to maintain top quality?
Sorry, this reply is very late. You probably already have your answer and a solution. But you don't specify what resolution/format/size/aspect that you want to deliver in. So if you intend to deliver in 4K, then any digital zoom will degrade the image. If you deliver in HD, then you can do up to a 2X blow-up before you start to degrade the image. That being said, you can typically got up to 120% over a 1:1 pixel ratio before the softness starts to become noticeable. However, it depends on the detail and action in the shot as to how much you can get away with.
FrameFlex does a good job, but tweak the settings. BorisFX BCC also has some filters if you have that installed. After Effects and Resolve do even better blow-ups.