OSMC/Kodi audio sync adjust

I am in the process of creating a new OSMC box based on an RPi4B from scratch (see my other thread about WiFi problems).
I have come as far as copying the source settings from an existing OSMC RPi3B box, so I can access the same video files (mp4 videos) via a samba share on the NAS using the same method/login.

I have discovered a problem I would like to know if it is possible to fix:

When I play a video (any of many) on the old OSMC it plays fine.
But when I do exactly the same on the new RPi4B based box there is noticable audio sync problems making it uncomfortable to view the videos on this OSMC.

So I wonder if there is a setting somewhere where I can adjust the Audio/Video delay to bring them into full sync?

Which version of Kodi is running on ‘old OSMC’? Same as ‘new RPi4B’?

You can adjust this when playing a video from the OSD context menu for Audio.

Copying settings files from an older Pi to Pi 4 can lead to playback problems and I would suggest avoiding this; particularly as you are also migrating across versions of OSMC

The olderversion which I compare audio to is up-to-date, i.e. the same as in a new install made today. It has been regularly updated when it shows that new versions are available.

Does this apply only to the video now playing?
I have noted that this is a difference between my new and old installation, i.e. it affects all mp4 videos I have looked at in the same way…
So I need it to be a globally active setting. I need something like 300 ms shift.

And how do I reach the “OSD context menu for Audio”???
The OSMC devices are both connected to an LG smart-TV by HDMI and I am using its remote control via the HDMI connection.

No, the idea here was NOT to copy anything but enter data into the various files manually (after looking at the defaults and what was present in the older install).
I have found earlier that upgrading Kodi/OSMC inline is sketchy especially if you do not do it regularly and in this case I need to go to a new major OSMC version.
So I will set it up from scratch.