If I already have a Chime Pro and one of my cameras is still lacking wifi service, what else can i purchase to help with the signal. I’M missing alerts due to this. PLEASE HELP

Try putting one of your existing WiFi Access Points as close to the camera as possible. If a doorbell on the otherside of the wall from it would be good. See if either of those helps before you look to purchase something.

I have my wifi and my chime pro as close as possibly can. The camera that is lacking is the one on my garage. Which is about 30ft away

Then temporarily move the camera to be closer to your WiFi. This is just to test to see if it is a WiFi signal issue or not.
If it is then you’ll need to get a WiFi access point closer to the camera.

Good luck!