A/C not working properly

Hello, I've come across your YouTube video on how to fix your A/C system in your car. My interesting issue is that my idle drops low then spike up and makes the car shake when the A/C button is pressed, but when it's not it idles fine with no drop in idle at all. I do have hardened engine mounts which is a cause of it, but it drops idle to the point it seems like it's going to stall (which is obvious, because the A/C button activates the compressor clutch), but when I drive the car and I come to a stop, idle drops down to let's say 600 RPMs, then spikes up to 1,500 then goes back to normal idle at 800-900. A/C clutch seems to be spinning at all times, but I assume it stops spinning when it drops in idle. Now I have an Acura Integra Type R motor swapped into my 1999 Civic Hatch, and I have friends who don't have this issue, I've had it for about 2 years and can't get my head around it. I've been to mechanics, electricians, and asked forum pages what the issue could be, and I've been told it's normal, but I don't think it is because other people have had A/C in their car without issues. I've done everything possible and done research, but I have zero idea. I could suspect condenser is on its way out? Or its out ages ago but it holds freon fine, have had the pressure checked and its holding good.