@pibew84514 mostly it depends on your clients.

The speed increases depend on the available wireless channels and the client hardware.

Pretty much all clients are 2 input x 2 output streams (I think streams is the right word) whereas routers with the higher quoted speeds are often 4x4 so the clients can't benefit from that.

If there wireless regulations in your area permit a good range of channels then the number of channels used in wireless connections can be larger (eg. 80Mhz, 160Mhz, 240Mhz or 320Mhz) in which case clients that have WiFi 6 6Ghz or WiFi 7 capability will sync at a faster rate. It's these higher frequencies that provide advantages when the clients driver can use them.

For example, the wireless regulations where I am mean it's hard for me to get 160Mhz), my BE85 (and my XE75, and probably a number of the WiFi 6 Decos) consistently use 160Mhz so my wifi 6 clients (both 6Ghz and 5Ghz) sync. at up to 2.4 Gbps.

So it's more about the clients and the channels that the devices can use.

I have to say that the clients drivers make a difference too, I have noticed that, IMHO, the 6 Ghz WiFi is not quite as good as the 5 Ghz yet but there are more channels available on the 6Ghz so it's useful even though I don't see the increased throughput now I expect I will in time.

And another thing that's WiFi 7 specific, that isn't implemented yet, the use of multiple contiguous channel blocks (not sure if that's more than two blocks) to overcome gaps in channels ranges so higher frequencies can be used. But that's almost certainly WiFi 7 specific.

What I don't know is if the Wifi 7 Deco units utilize the WiFi 7 features they do have now for backhaul and which features are used ...

The obvious thing here is that if they do use the WiFi 7 features they have for backhaul communications then the higher end hardware is a better choice.

But there's nothing that really says they do although it's implied ... 

For example you can enable Multi-Link Operation but that's for clients and there's nothing that says whether this is used for backhaul and if the client MLO needs needs to be enabled for it to be used for backhaul.

But personally I like to go for the higher end hardware, really mostly becuase I can.