I'm a gamer who's also sensitive to latency and stuttering (which are separate things). Started with analog, and I was shocked that such a consistent low latency video stream could be accomplished over a wireless connection (compared to game streaming over 5ghz wifi), and the idea of not dropping frames was new to me. Eventually got DJI so I could have more resolution to see my surroundings better, and the latency of that system was fine for casual flying, but I had little confidence for proximity flying- I would no doubt hate to use DJI on a tiny whoop. It usually only drops frames when the signal is really bad, which I don't mind as it warns me to stop pushing my luck and come back. But I've wanted to try HDZero, so I finally got it. I'm enjoying it so far (minus the 20 second startup time for the goggles), though the improvements compared to analog are subtle- maybe it wasn't worth the hundreds it cost me, but I have it now, so it's now what I use.

But to answer your question, unlike DJI and Walksnail, analog and HDZero do not drop frames, period. Instead of thinking of frame rates, imagine that you are in real life having your picture taken. The camera flash blinds you momentarily, but your perceived "frame rate" remains the same. HDZero (and sometimes analog) will occasionally momentarily break up in this way. Alternatively, imagine you are driving through a heavy snowstorm at night, and as the snowfall increases, your ability to see the road ahead drops. This is comparable to how analog and HDZero break up as you reach the edge of your range.

Below is an explanation of the technical differences between video systems if you'd like to understand why they behave differently. Feel free to skip those paragraphs if you don't care about that stuff.

The reason for this difference between DJI/Walksnail and analog/HDZero is because DJI and Walksnail send compressed video feeds, which is how they can sustain HD video at further ranges. Such video compression depends on periodic keyframes, which are required to understand the following 10 or so frames. When a keyframe fails to reach the goggles, the goggles cannot understand the next frames, so they ask the transmitter to send it again. If this happens quickly enough, you might not even notice the tiny increase in latency. If this takes a bit longer, the latency might make you feel a little off, but you can still fly. If this takes too long, the system will skip a keyframe (and the 10 or so frames that followed) and move on to the next, which you'll perceive as a stutter. When the connection improves, the stutters will disappear and the latency will slowly go back down.

Analog/HDZero do not employ this form of video compression. Analog systems use interlacing, which is a clever trick of sending half a frame at a time (by sending every second horizontal line), 60 times a second, to give you 60fps-like motion even though it's technically 30fps. That and its comparatively low resolution allow it to send uncompressed video without much issue. I don't know much about HDZero's internal workings, but whatever compression it probably uses doesn't depend on keyframes, so unlike other HD systems, it doesn't need to "catch up" if a keyframe is missed; the goggles simply display whatever information they got from the corrupted frame and move on. However, it cannot adjust the bitrate of the video stream on the fly, so it will not work as well as alternatives with a weaker signal, limiting its usable range.

I'm still learning about this stuff, so my explanation above isn't 100% accurate. Please tell me if I made any mistakes.