NETGEAR Nighthawk R7960P wifi slower on devices than is says on the app

I will try and give as much additional information as I have right now specifically because I will not return to my son's house until tomorrow.
The modem is a Spectrum issued Sercomm ES2251
when I installed the router, it said it was searching for firmware updates, it found and installed the latest update I assumed.
The only devices that were installed and tested were
1) the Spectrum modem
2) the router in discussion
3) Iphone 13 Pro Max
4) Acer G3-571
- this router was first tested using the netgear nighthawk app on a iphone 13 pro max, the app gave me a speed of 450 Mbps. I then tested all 3 bands on a speedtest.net app and got 80 Mbps on 2.4ghz and 140 Mbps on both 5 ghz frequencies. Originally, it was tested without smart connect but once I was concerned with the speeds, I tried to enable smart connect which yielded the same results of 140Mbps as it defaulted to the 5ghz. I fiddled with this on the iphone quite a bit at first only because I could not get it to open on my laptop (Acer G3-571). I eventually got my laptop to connect on 192.168.1.1 after, I went to speedtest.net and got the same results as on the iphone. I only had 1 device testing at a time, this is my son's first home and nobody is currently living there so it was only me testing. I did see a number (roughly 10 or so) other networks in range. I also tried the speedtest app for windows as I remembered reading somewhere that speeds over 100 Mbps are not always correct with the website and that the app is recommended for higher speeds.
-I then decided to do what I know the ISP would say and bypass the router and just hook my laptop directly to the modem. In doing so, my results at speedtest.net were >450 Mbps. Hence my leaning towards the router or it's configuration being the issue.
-I know wired is preferred, in a perfect world, I would have a wired connection everywhere. This house was built in 1906 with plaster walls and wool insulation. Wiring this house will not be something I will attempt. I wanted a decent wifi because of this and when I came across this router, it seemed to fit the bill.
-the channels were default to auto as far as I know. I did not do any adjustments in the configuration on the router page except accepting the free trial of the security software. I declined disney circle.
-the wireless card on the computer is Qualcomm Atheros QCA61x4A Wireless Network Adapter but it yielded the same results as the iphone 13 pro max.

I think I covered everything. This is a used router that I found at goodwill so I am leaning more towards the router being the problem but I figured I would reach out to people that know more than I for help before I throw in the towel and just buy some brand new TP link or something cheap as my son's budget is small.
Again, thank you for any and all help, it is really appreciated.