BEIJING—Global stock markets and U.S. futures were mostly higher Monday on 2022′s first trading day after Wall Street ended last year with a double-digit gain. Frankfurt and Paris opened higher while Seoul and India advanced. Hong Kong retreated. Markets in Britain, China, Japan, and Australia were closed. Wall Street’s benchmark S&P 500 index slipped Friday amid lingering worries about the coronavirus’s omicron variant but ended 2021 with an annual gain of 26.9 percent. “It remains to be seen to what extent the optimism of the New Year will be reflected in financial markets,” said Venkateswaran Levanya of Mizuho Bank in a report. In early trading, Frankfurt’s DAX gained 0.8 percent to 16,010.77 and the CAC 40 in Paris added 0.9 percent to 7,213.57. On Wall Street, futures for the S&P 500 and the Dow Jones Industrial Average were 0.4 percent higher. On Friday, the S&P 500 slipped 0.3 percent and …