Bridge Mode on Xfinity XB8 vs AP Mode on Nighthawk RS700

As the subject reads, I am looking for advice/opinions on what is the best configuration to use for my home network. I primarily purchased the RS700 to have better Wi-Fi coverage since the modem that Xfinity provides is not the greatest. It gets the job done, but could be much better. The additional Ethernet ports are a plus too, and I have an 8-port 2.5GB switch implemented as well. I use the Gigabit Extra plan at 1200Mbps.

My home is 2, technically 3, floors. There is a ground level with a den, which is where I keep my XB8 modem and only two devices need an Ethernet cable, those being my Xbox and PC. Since the modem is acting as a router still, I use 2 of the 4 Ethernet ports; one for the RS700 and one for my Xbox. My PC is plugged into the switch on the second floor. The second floor, my living room, has most of the devices using Ethernet and Wi-Fi (PS4, Nintendo Switch, Xbox, Smart TV, and a PC). The RS700 is also up here. The Wi-Fi devices are smart home devices, phones, laptops, and tablets. The top floor has two bedrooms just using Wi-Fi since there's a Fire Stick and a smart TV. Maybe hard-wire those at some point but for right now, they're wireless.

I just don't know if Bridge Mode on the Xfinity modem is better than using AP mode on the RS700, or vice versa. I know using AP mode on the RS700 will deactivate Netgear Armor and I currently have a free trial for a few months, but don't really see myself paying for it after the trial is over. My Xfinity modem has advanced security protection by default so that would take its place. If I use AP mode, I can keep my wires the way they're currently connected.

If I use bridge mode and have the RS700 act as the router, then I need to move the existing switch or add a new switch to the den since only one Ethernet port will work on the modem, and I prefer my Xbox and PC to use Ethernet. Most likely, I'd add a small switch to the den since there are more devices to connect to on the upper floors. Then at that point, it might make more sense to just invest in my own modem and save the rental fees.

Also, having separate networks is a tad bit annoying so having them as one would be nice, and I know it's recommended practice to do that anyway. I just plugged everything in, set it up, and left it for a month to made sure everything worked as-is. The Xbox gives a Double NAT warning, but has never gave me any performance or latency issues that I could see.

What would you do in my scenario? What makes the most sense here? Thanks in advance for your input.