Had Activity Monitor open at the point of crash this time: 826.6 MB real memory, 121.17 GB virtual memory. Which is normal for Discord + the "JavaScript memory cage", the new process looks similar and so did the equivalent Safari process, IIRC. There is a CPU spike in the Activity Monitor history but I think it's just as likely to be the crash log collection as an actual spike in the WebKit process.
The worst part is I was just idling this time. Previously it'd been happening while I was taking an action in Discord, though the action varied: sending a reaction, playing an embedded video, … But this time, given the reload state, I think it was just sitting there as the frontmost tab, receiving the usual updates in the background.