AirPort Extreme 802.11ac and Gigabit Internet

I wanted to update with more specifics about my wireless setup.

My AirPort is acting as a bridge, it apparently cannot act as the router for technical reasons I am not 100% clear on. There is a router provided by my ISP (Century Link) that is assigning the IP addresses and my AirPort is in Bridge mode. Additionally, there is a 2nd AirPort Extreme acting as an extender, though I've been testing primarily off the main AirPort, I have gotten similar tests off the 2nd AirPort.

I have tested directly from the modem provided and get around 850 Mbps down and around 500 up. That's shy of the advertised 1Gbps Down 1Gbps Up, but honestly still plenty fast for me. Much faster on the downloads side though than anything I've gotten over wireless. And truthfully, the uploads are just as important. I am into photography, and I upload tons of data to the cloud. (Still, I'll be working with my ISP on the modem side just to make sure I'm maximizing my service.)

I do not have separate 2.4 GHz and 5 GHz SSIDs, (but I did confirm that I was on the 5 GHz before testing the speed). I want it that way so that I can take advantage of the band steering within the router. (Though I'm not sure how good it is.)

I've been using WiFi Explorer to confirm which AirPort and which band I was on prior to testing.

If I need a new router, that's fine, I understand the AirPort Extreme is now 5 years old and it may just not be able to keep up with new tech. I've been doing a ton of research on this, but networking is a huge area of weakness for me. I don't understand it a tenth as well as I'd like.

Yeah, I had a feeling and have been coming to that conclusion. But I wanted to make sure a new router would actually make a difference before diving into one. Still, it also sounds like I should be getting at least a little higher download speeds via WiFi.

Bob, thanks for your clarifying questions. I've added a reply below with some more details on my setup and the testing I've done that answers your questions.

Based on your response, it sounds like I should be getting higher speeds than I am now, but that a new wireless router would likely better utilize the bandwidth I have. Luckily my main AppleTV and many of my IoT devices are plugged directly into the router via a switch. Though I do have three security cameras that are wireless, plus our computers and all our iOS devices. I've been really tempted to try running some Cat5 cable from my router/modem to my desk and to my second AirPort Extreme.

That's a good call. I'm honestly a bit torn between wanting to get the most out of what I'm paying for, and the reality that 200 Mbps down and 500 Mbps up is probably just fine. But if I got it up to 500 on both, I'd probably just leave well enough alone. CenturyLink doesn't have any tiers between 100 down / 50 up and 1000 down / 1000 up, otherwise I might have chosen a different tier.

Bob for the win! That got me 500 up and 500 down. That's good enough to keep the AirPorts around for a bit longer at least. Plenty fast for my needs.

EDIT: Bob still wins for helping me figure out the issue. For a brief moment, I had 500 up, 500 down. And then I reconnected my 2nd AirPort and my download speeds were brought back down to 200 Mbps. Turns out the AirPort can handle that throughput on its own, but as soon as I extended, even if my device was running off the main AirPort, the download speed is more than halved.