VST: Reaper sync does not really work

[NSNS33]

I can't dismiss this not being an user error at all, but:

1. Everything is on a single machine, local network.
2. Link Start Stop Sync is active in Live.
3. When sending audio from Live, I use no VST in Live (I use the native Link Audio) and I use one VST receive in Reaper. The live reports no visible peers (only "1 Link") but the phase is visually synced.
4. The opposite way, I use single VST send in Reaper and single VST receive on an audio track in Live. In that case I sometimes see a peer if I restart (turn off/on) Link in Live.
5. The recorded audio is completely desynched with no predictable offsets in both directions.
6. I can see the incoming audio drifting in time in the VST's oscilloscope.
7. Visually, the phase of the transports (Live phase and phase in the VST plugin) seems to be synched properly in both cases.
8. In all cases, the transport sync is not really automatic and requires user's manual trigger or automation of the VST's transport (play/pause) button. There is no project/global transport sync for the play trigger nor time (actual matching measures beyond the phase start). I am not sure if this was intended or not - just something I have noticed. I have tried to trigger record in Reaper and then trigger the VST's transport button in random places and also at exactly automated spots. The phase seems to match in both cases but both lead to identically unpredictable, desynched results.

I can provide more details if you can guide me through more debug steps. For example, it is not exactly clear to me, what does the Live's Link latency settings do but changing it didn't seem to do anything predictable.

[NSNS33]

Again, I am not sure if I get it but, currently, what is the point of the phase sync if it doesn't respect the DAW timeline at all? I would expect it to be synchable based on the VST's timeline automation of the transport play/pause button or derived from the DAW transport state. Otherwise there is absolutely no chance of synching the peers in global time if Link runs in a separate session based on the moment the VST is loaded while completely disregarding the transport state of the DAW running the VST.

Since the VST plugin can give Live the Link start/sync command (impossible vice versa, as the VST plugin cannot access Reaper's transport controls), there is a clear opportunity to use this for synching the DAWs transport start times. You start transport in Reaper, the VST plugin in Reaper automatically resets the phase and sends the Link start/sync command to Live.

The way it works now completely disqualifies any time-based effects usage in peers.

Currently, in this particular use case, the VST is a mere audio over network, with no added benefit to that of ReaStream.

Btw, I don't wanna sound like I am complaining, I am just trying to get it. I am puzzled.

[NSNS33]

When I use ReaBlink to sync the transports via Link, everything gets, obviously, better but then, the recorded audio is still 22 ms late in Reaper and the delay changes based on the soundcard buffer size (512 samples give those 22 ms, 64 samples give 13 ms). I really fail to see the point of the VST plugin in this particular case. As mentioned before, ReaStream would do the same job. What is the Link Audio timestamping for in this case? Moreover the latency drifts, so it is not sample accurate at all (but I don't know if that is because of Link or Link Audio or ReaBlink implementation). And could it be used for the plugin PDC reporting so that it can be latency compensated?

Still puzzled.