BEIJING—The Chinese Communist Party (CCP) is tightening political control over China’s internet giants and tapping their wealth to pay for its ambitions to reduce reliance on U.S. and European technology. Anti-monopoly and data security crackdowns starting in late 2020 have shaken the industry. Investor jitters have knocked more than $1.3 trillion off the total market value of e-commerce platform Alibaba, games and social media operator Tencent and other tech giants. The CCP says anti-monopoly enforcement will be a priority through 2025. It says competition will help create jobs and raise living standards. The CCP seems likely to stay the course even if economic growth suffers, say businesspeople, lawyers, and economists. Lester Ross, head of the Beijing office of law firm WilmerHale, said that Chinese leaders don’t want to reimpose direct control of the economy but want private sector companies to align with the CCP’s plans. “What they are worried about …