I don't know what to say honestly to help, because no one wants to fix the issues for OBS / NDI currently, and that's kinda the nasty truth. You can fix it for a day or two, but problems will come back.
So you're kinda on your own to find out what your system will "tolerate", or should I say what kind of "quality" you personally will tolerate on your streams.
I did mention several times in the past that newer versions of OBS 27 were having the desync issues.
Neither OBS or NDI peeps wanted to fix it, even though it's literally there, as in just look up what was changed in OBS in version 27.1 or something and the later ones to see where the problem started, no one did.
I did mention that the new NDI Tools work, and I think version 4.6 was the best, but NDI removed them.
So we're still stuck on 4.5.1 Github Runtimes, and now there is the issue that NDI 5 Runtimes is also lost (or the outdated version is only backed?), while I think NDI Tools 5.0 have stutters issues. No one has backups or fixes for these.
I did mention that the best you can fix NDI with is by having intermittent "audio drops", as in every couple of minutes to hours, your audio will "skip" a couple of frames trying to resync.
It's annoying if you focus on it, but not really noticeable, and that's the best you can hope for. Nobody bothered using this information to trace back the "audio buffering issue", that I think only NDI 4.9.2 partially fixed.
I did mention a bug about having too many NDI specific outputs causing the Streaming PC for example to get taxed by OBS and disconnecting the PC's connection, while also potentially desyncing the whole audio by several seconds fully, no one cared.
I did mention also that the new OBS-NDI has "audio capture issues", as in you need to start a 3D software first (game for example) and THEN OBS afterwards, otherwise it will desync the audio on the outputs.
Most apparent with OBS and NDI on a second screen before starting a game (even VLC desyncs it), it could be related to Shader Caching or something, but no one bothered checking up on this issue since it's "visual" and not a "real" problem, whatever that means.
And just recently, as in today, I found out OBS stutters videos every couple of minutes to an hour with the latest NDI Plugin. I has some videos be completely desynced as a local recording.
Everyone is saying to use NDI 4.10.1, but it seems like no one noticed it's causes video buffering/latency issues for stressed GPU's, meaning unless you have 2 GPU Encoding chips (which only exists on high end GPU's) for example, even recording a video will have the same stutters and audio drops as in the stream, sometimes worse, just adding extra work for people to fix in a video editor.
The best part? Old OBS with 4.9 doesn't have this Local Recording issue with GPU videos at least, and I think 4.9.2 for OBS 28 also fixes this issue. Yet it seems like no one notices any of these issues or can do anything about it, so we're stuck with what we have, or with plenty of contradicting information.
I think if OBS gets another update that breaks the current 4.9.2 NDI Plugins, or introduces anymore issues with the NDI Tools, NDI will be pretty much dead at that point since it's barely works at this point.
At that point you will need to use the Teleport Plugin. It would be perfect if the Teleport Plugin could use QuickSync for example to do it's work, but sadly it needs to use about 10% of a CPU's power, which has it's own set of issues.
