Probably not, especially if you’re trying to perform any sort of ‘recognition’ type of image processing on the video feed from those cameras. I really don’t think you’ll see much performance different between your existing RPI 4 and a HA Green.
Have you considered running HAOS on a more powerful Intel NUC style small form factor computer? With the correct CPU and memory, you should be able to handle video processing much better than what a RPi or HA Green can handle.