VW Polo: Oil pressure tests, from cold to normal engine temperature, with an oil pressure gauge

The oil pressure light on the instrument: will light up with beeps when the oil pressure at the top of the engine drops below 0.5 bars. The oil pressure relief valve: is incorporated into the oil pump. It closes when the pressure is below the set threshold. It opens when the oil pressure is over 3 bars. The oil pressure gauge needle shaking? I think this is due to the operation of the oil relief valve. The oil pressure relief valve opens at a set pressure and closed at a lower pressure. Therefore when the oil pressure is high, the relief valve may be in the open/close states frequently and cause the shaking. What if the oil pressure/flow is very high so that even the relief valve is open the pressure does not drop to the closing pressure? I guess it may just keep in open position and no shaking(?). Hope this video help. Your comments, suggestions and subscription will be highly appreciated. Thank you.