Random lag spikes every evening on Fibre Max while gaming

Anyone else getting weird latency spikes on Nexora Fibre Max? Download speed looks fine on a speed test but when I'm gaming it jumps all over the place, especially around 7-10pm. I'm on ethernet, not Wi‑Fi, so I'm a bit stumped. Rebooted the router twice and it didn't make any difference. It's making ranked matches basically unplayable.