290 mbps wifi, 340 wired

A First World, urban issue, I confess:

On my 300 Mbps service, wired I get 340 Mbps. On 5 Gigahertz AC Wi-Fi, it goes up to about 290, even if I’m right on top of it.

Changing channels doesn’t help either. Within my 80 MHz channel, there is one other Wi-Fi network. There are no channels with zero other networks. The Wispy folks said my 80 MHz channel reservation is fine on 5 gigahertz AC. That the protocol takes care of things properly and I’m not just hogging the channel from others.

So, have I hit my limit at 290 Mbps, concerning the networks around me? Is there anything else to tweak or try?

It’s not exactly the end of the world as it is. I’m just trying to maximize what I have.

It’s not worth taking too much time to fiddle with… It would also be nice to know whether it would not pay to ever upgrade my internet service to a higher bandwidth.

Thank you