Stopping down doesn't always give you sharper images. You may run into diffraction softening.
Focusing and then stopping down may shift your focal plane. Try to focus at your chosen aperture.
Try to use the electronic shutter function for astro photography. Even the shutter moving across the sensor can cause vibrations.
The 500 rule is useful for astro, but with modern higher resolution sensors, the NPF rule is better suited.
Not getting amazing astro shots? You may need to modify or buy a camera that is sensitive to Hα (Hydrogen-alpha) removing the infrared/IR filter off your camera will allow you to shoot full spectrum. Although you will need something to only allow 450 to 520nm and from 640 to 690nm into your sensor.
Sensors will always have dead or stuck pixels. You can take 10-20 black frames to try to help your image processor find and erase them.
Optical vignetting is common when you shoot wide open. Stop down 2-3 stops from your max aperture to try and remove the effect.
Shooting expired film is fine, just make sure you over expose 1 stop per decade it's expired. So a 20 year old film, shoot 2 stops over exposed.
Anything that uses GPS time (many devices use GPS as Stratum 0) would break. For example stock exchanges that use RF would become out of sync.
This includes traffic lights and various other quality of life improvements that rely on LTE and 5G connectivity. Also all mobile data would be depreciated.
Many wars that involved any precision munitions would stop.
Many air gapped facilities use GPS time as opposed to NTP which includes powerplants nuclear safe guards, and industrial systems will start to become depreciated.
Just remember, the media is owned by the rich.