A pair of proposals would invest in infrastructure, education, work force development and fighting climate change, with the aim of making the economy more productive. President Biden’s economic advisers are preparing to recommend spending as much as $3 trillion on a sweeping set of efforts aimed at boosting the economy, reducing carbon emissions and narrowing economic inequality, beginning with a giant infrastructure plan that may be financed in part through tax increases on corporations and the rich. After months of internal debate, Mr. Biden’s advisers are expected to present a proposal to the president this week that recommends carving his...