Oil Pressure Issues When Starting Car

Good day.

The problem with my Golf III ALE, which has 329,000 km on the odometer, is the lack of oil pressure when starting. The longer it has been standing, the longer the oil pressure warning light stays on when starting the engine. The warning light accurately reflects the situation, as you can clearly hear the engine running without lubrication.
The strange thing is that, despite having been stationary for a long time, it sometimes starts without any oil pressure problems.

'So far, I've just been waiting for 2 to 5 seconds, adding another 2 seconds for good measure, before starting. It doesn't really bother me, but if others don't do the same, the turbo could break down due to insufficient lubrication of the sliding bearings.'

Is there a check valve somewhere that prevents the oil gallery from draining?
Next week, I планирую to change the oil (the interval has been reached; currently using Motul 10W40), is there anything I should check?

Even after driving for hundreds of kilometers on the highway and at high RPMs, there is no oil pressure problem, which is why I can rule out bearing issues.

Does anyone have any idea what it could be?

Happy Sunday.

P.S. What surprises me is the inconsistency in the blinking duration; after all, it blinks for many people in the first few seconds.