Ring Alarm Pro - Built-in Eero Pro 6 or Simply a Eero 6

Hello, I currently have a well defined Eero meshed network based upon Eero Pro 6 units, and curious about upgrading my current Ring Alarm system to a Ring Alarm Pro. I have been reading a feature online product reviews and community posts/responses but can't seem to get a definite answer to a few questions. First, is the built in Eero router a Eero Pro 6 or just a Eero 6? I wouldn't want to downgrade my Gateway from a Pro 6 to just a 6. Also, the location of my ISP ONT isn't suitable as a location for my Alarm Base Station. Hence another reason why I would prefer avoiding having to define the Alarm Pro as also the main gateway. So exactly what features would be missing? Least I can then determine exactly how important those features are. Don't really see or understand why it needs to be the main router. Or at least can't appropriately interact with another Eero Gateway to still offer full functionality. Don't want to need to start running wires throughout the house; which I why I went with the Eero meshed network to begin with. Thanks.