Dude, completely same scenario that weirdly began roughly around the same time you reported that. I've been bashing my head into my keyboard all year: I was with Piglin to offload my almost 10-year-old laptop from being a dedicated with 0.6/mb upload wifi so that my friends could have fun, and everything was going swell until it literally wasn't. I've found NO help across the entire damn internet to understand what's wrong and why, nobody can tell me how to read Spark, and nothing seems to be able to prevent the irrepairable flash-crash that just gets worse with every startup.
So far I've crashed a server that had access to 8GB of RAM (my provider), my cruddy old laptop (which somehow outperformed them during the testing area, until yesterday...), and now my latest i7 laptop with more than enough processing power (32 logis) to handle the situation, yet, I get a nice blue sky at 100% CPU logging on the server. I'm up to here with trying to figure it out after a year long battle!!