Air conditioning related.

I please have a question regarding an ac that I have checked on a 1999 Toyota tacoma 4.7 . right off the bat I saw it has a leak on the high pressure service valve, but when I hooked the gauges I saw 70 psi of pressure in the low side and about the same pressure on the high side, and if I turned ac switch on, compressor clutch engaged but the low pressure gauge goes too low meaning it does not have freon. . now the question is, is it possible that the air has less pressure than the freon and thats why it holds air but the freon leaks out whithin days. ? i did not get that, and now if I put a vaccum pump for half and hour or so, do i have to put all of the amount of oil that the compressor takes? thank you Mr Paul. I have been watching your videos since 2019, probably there is a video where you explained these but maybe I missed it.

With the compressor off, both sides will equalize. So it's normal that whatever pressure you see in the high side will be the same in the low side at rest.
The charge is measured in weight, not pressure, so you really can't tell if the system if actually "full" by just a pressure measurement, all though you can get a good idea.
As you noted, since the low side goes very low when the compressor is on, that indicates a low charge. I wouldn't exactly say it is "empty", because the compressor does come on and there is pressure in the system, but it sounds like the charge is definitely low.
To answer your question about the vacuum pump, you will never pull all the oil out of the system with the vacuum pump, it is not possible or necessary.
With no leaks, you should be able to pull the system to very close to -30inhg. If it won't go that far into vacuum, there is a leak. It should hold this vacuum for a very long time. If it does not, there may be a leak. I say MAY be a leak, because I know my recovery machine won't keep a vacuum on the system for a very long time at rest.
If it is determined there is a leak, Scanner Danner has shown us that you can evacuate the system, pressurize the system with air (I like 100psi or more), and monitor the gauges. There should be no appreciable loss of pressure. If there is, then you can locate the leak with soap and water.