This is one of the risks of using the Hubitat websocket and why the proxy server is being developed..
Check this out... This is Hub 1, which is my 2nd floor hub. 95+% of device activity flows outward to to the server. Look at the proxyEvents metrics which are over about 31 hours since I last restarted the proxy..
1,190,830 events received by the proxy from the server hub websocket but only 510 events forwarded to the Hub 1. Thats almost 1.2 million calls to parse() that have been avoided.
If you keep having Hub slowdowns I would suggest switching over to http for a while. I suspect event saturation on the websocket might be dragging the hub down.
Oh, and Happy New Year!