I have a 20psi switch I plan (one day) to fit to one of my cars. If I do so it will be in conjunction with with te original one. The 20psi one will have a bright LED fitted, and the idea is to wire it so only comes live once the car is running (not while cranking)
Incidentally, there is an adjustable switch, preset at 20psi and only £20 from Demon Tweeks
https://www.ebay.co.uk/itm/141714467969 which may be an idea if you plan to pursue this.
But better is an oil npressure gauge if you have concerns about oil pressure or are inquisitive. I have never bought a new one, and had a number of used ones, mainly Smiths or Yazuka. Not all accurately calibrated but within 10% of each other, mostly closer from memory.
It was useful when I had a 1500 engine in my Toledo. With std mineral oil, when hot at idle, the pressure was about 25psi. This increased a little by changing to the much-acclaimed VR! 20/50, but went over 30psi with millers CSS 20/60. When running this equated to 60psi, against the mineral 50psi.
Anyway, I digress. A 20 psi oil switch may trigger at idle on a slant engine. I have had a few cars where the std one would flicker at idle, but were fine when running (usually the fix was a new set of BE shells).
I am not sure if any of that helps.... But I try to avoid extra "worry gauges" as they are so damn distracting. So for me the 20psi switch may, just may, be the way forward for me. Jury is still out.