So to close out this issue in case others are having a similar problem, I’ll let you know where I’m at. A lot of the troubleshooting was handled via private message (primarily with @grahamh) so it is, unfortunately, not visible here. I’ll provide a short summary.
Ultimately the Vero V was unable to play mpeg2 480i in software with deinterlacing active (no whitelist). A lot of stuttering and dropped frames. Both 29.97 and 25fps seem to be affected with 29.97 appearing to drop frames at a higher rate. A previous sample of various types of interlaced files provided by @angry.sardine in the below post provides a couple of examples and is similar to what I experience with my own files.
The relevant files are Earthshock and Time Flight. These are the two files of those samples that mediainfo lists as interlaced.
Given the old nature of the mpeg2 codec and other possible workarounds, I don’t think there’s an appetite to chase the issue down in the code, which I can understand. I believe having the relevant resolutions and framerates whitelisted resolves a large portion (all?) of the stuttering problem but it unfortunately causes a lot of problems with the aspect ratio on my setup. This will probably be my next issue posted to the boards.
For now, my short-term solution is to turn on hardware decoding for SD MPEG2 content. It seems to resolve the issue with the stutter. My only apprehension is that long ago I turned it off (Vero 4K+) because it was causing issues. Perhaps those have been resolved over the hardware and software evolutions. Time will tell.
A quick shout out to @grahamh and @angry.sardine. Both were very helpful in trying to understand the problem and possible resolutions.