Frequent 'Spurous retransmissions'

I have the following setup:

At peak Wifi traffic, I see that some sites on the inteet are re-sending packets needlessly, triggering 'Spurious re-transmission' messages in Wireshark. This finally results in Time-outs, and loss of coection.

I suspect that the inteet sites are not allowing for the extra delays 'behind the scenes' of the wifi link, and just re-transmits. Is this a correct assumption?

As I don't have control over the Inteet sites' behaviour, I suspect I could improve the situation installing a proxy in the server which ACKs the site's packets and takes of the Wifi links. Maybe a program like TinyProxy? (I have a solid coection to the sites from the Server).

Or is there other tweaking which can be done before installing the proxy?

(Note: I am not a network expert - and the setup is a small-scale home setup. Machines are Linux)