Any tips for addressing stuttering?

Hullo,

Boosteroid has been working well for me up until the last month or so. Now all games stutter consistently every second. The stutters are very brief - but are enough that I've stopped trying to play anything.

Does anyone have any tips? Relevant details as follows:

Southern Sweden. Time of day doesn't make any difference.

300MB up & down. Less than 20ms latency. Very few other devices running on my network which has a Asus router prioritising my laptop. Can't use ethernet, unfortunately. But very close to the router. Nothing on the network has changed since before the stuttering started.

Using both the app and browser on a Macbook M1 Pro.

Many thanks,