Day by day increasing delay on video feed from reolink camera

most of my cameras handled by synology SS are 720/1080p max.(I got 18 of those).
I just bought a new reolink 523W and obviously that one has way better resolution.

what I notice is that right from boot, the lag is 1-2 seconds…nothing unusual.
after a day…it’s at least 10-20 seconds…
even the smaller resolution (stream 2 is 640x480) is suffering to some extent from this increasing lag.

I am not quite sure what the deal is. any parameter tweaks?

Cheers
vincent