I use both and have been spot on. Some will notice issues with vehicles at night (especially if running color) as the camera needs time to recognize the object and then trigger, but it is based on limitation of the location of the camera and viewpoint rather than limitations with the AI itself.
And yeah based on your system, you may need to keep some on that 3rd party, but other cameras you can probably use it within the camera.
Blue Iris allows MQTT, but I do not use it so I do not know the specifics as to if you could migrate what you are doing to that or not. But maybe if offloading a camera or two off of Deepstack brings system usage down maybe it would be of benefit to you. Last thing you need is CPU maxing out or getting that error you posted in other thread happening at the wrong time and missing something.