Constant Ping Spikes despite Strong Wifi

Ever since the last nightly maintenance, my wifi has been undergoing constant ping spikes, maintaining a soft 30 ms and below for about 10-15 seconds at a time before spiking to about 200 and above, going up so far as 2,000 ms at times. I've reset my router a number of times both manually and through the app and followed the steps explained in the troubleshooting guide, and yet, though my wifi's speed is consistently strong, my ping continues to spike repeatedly. Resetting the router generally causes it to function as normal for about 10 minutes, but it returns to 200 - 1000 ms rather consistently after that. This didn't occur before the maintenance and only started occurring roughly after, so I've verified that it's not cause of any app or device in particular, as I've tested this over multiple devices and apps. Generally, this isn't an issue for low-importance tasks, but I'm unable to properly game or call without constant ms spikes being an issue. Any help would be appreciated.