Many state legislatures have research service bureaus to conduct non-partisan research at the request of individual lawmakers or committees. At best, these offices are staffed with professional analysts with advanced degrees or other professional qualifications, and the bureaus make these reports available on their websites. Unfortunately not all states prioritize these services, and there's great variation in the scope and quality of these efforts among the states. (Connecticut's Office of Legislative Research is an example of a bureau that provides extensive issue and bill analysis on topics like cannabis). The names of states' legislative research bureaus vary; Texas' House Research Organization, and Colorado's Legislative Council Staff are example of legislative research bureaus.
Ballotpedia offers a directory of state legislative research service bureaus here - many links are dead, but the directory provides, at least, the name of the bureau to make searching for it a little easier!