To preface: I am not advocating for the total removal of the feature, only for it to be relegated to a debug option as it is a very useful feature but should not be immediately exposed to users who may not know the implications of it.
After doing quite a bit of troubleshooting for other users, it's become apparent that leaving the 'Realtime' Reflection Detail in the Advanced Graphics panel from project testing has caused issues. It's ended up being interpreted as 'max' for that setting, when in reality it is an option that PCs 10 years down the line won't be able to handle in all but the most curated scenes. I have had people get upset with me saying that the viewer is awful because they can't 'max it out' ie enable 'Realtime Probes'.
For context: Realtime causes the nearest Dynamic probe to update every frame. This essentially causes the viewer to render the scene 6 more times. As far as I'm aware there are no known hardware configurations, base or overclocked, that could render common scenes in SL at any reasonable framerate with that enabled. Anytime I've used it I had to make a very highly optimized scene to manage reasonable performance, and I'm on a RX 6800 and Intel 14700K!