Diversifying heavy position in AMZN

Have held an incredible amount of AMZN stock (vested RSU’) but never diversified out. Well I paid for it when it dropped from $3700 down to $2200 now. My thought process was “time in the market beats timing in the market”

I actually still believe in the company long run but now learning about the importance for diversification. I am considering selling 85% of it (gradually over the next year or so) to diversify across sectors and large cap/small cap.

Would it be dumb to diversify now? Would it be “locking in my losses”? Overall I’m still up positively with the stock lot.