(Bloomberg) -- China’s internet firms are revving up efforts to outdo each other since Beijing began to wind back its bruising internet crackdown, spurring an abrupt surge in competition that’s threatening margins and spooking investors.Most Read from BloombergYou Want at Least $3 Million in Savings to Retire ComfortablyThe Biden White House Operated Under Cloak-and-Dagger Secrecy to Plan His Ukraine TripUS-China Meeting Only Worsens Tensions Over Balloon, RussiaStocks Muted, US Futures Fall as