@Zenith22,

At this level of tuning, there are a few things you can do to bump it up.

I would start with first changing your router's DNS service to a common service, such as Cloudflare or Google. I have seen pretty dramatic increases when changing this. Otherwise, you may check to see what DNS service your ISP uses for their routers/service. This could also have an affect on what server you are testing with, even if you choose the same one, it may be taking a different route there.

Is your ISP modem a gateway(capable of providing Wi-Fi), or just a modem?

I would also recommend setting your QoS to a speed above what you expect from your ISP and setting the PC as high priority- otherwise, disable QoS entirely.