Affordable products and investment are key to real prosperity for any nation. Mexico's new tariffs on China are going to exclude it from Chinese investment, and the opportunity to be a major manufacturing center for Latin American market. US investment in Mexico is also being stiffled. Any Mexican that would want to invest in Mexico does so knowing that US will prevent access to its market, and they need to compete with China in other Latin American markets.
OP highlights that US auto sector (owners) was making money in Mexican market, and Chinese parts imports did make US cars cheaper too.
Cost of living is just as much of a pluralist prosperity factor as incomes/jobs. The policy harms both significantly, with car ownership generally considered a prosperity measure, but one that is only attained with affordability.
Will Mexico's appeasement of US avoid expanding the war on Venezuela to Mexico? No.