That's a bit misleading. BRK is down a lot if you measure from Jan 1, 2020. From other dates, it's doing decently.
"Berkshire just posted the largest-ever loss by an S&P 500 company." That's because of new mark-to-market accounting. BRK's operating insurance holdings are very nicely profitable.
BRK's cash stash of $135 billion is brilliant. I don't like banks, but he was right about banks being pretty clean these days.
BRK is rock solid. Plenty of corps aren't nowadays.