The loss of faith in corpos is greatly overstated. Phase Connect had 3K applications for Gen 3, and Hololive had, what, 10K submissions for their last EN gen? Quality corpos are in high demand and those hiring are spoiled for choice. The only people who are complaining are vtweeters who were never interested nor in the running in the first place.
What we can learn from Nijisanji is that you should do your due diligence about any prospective corpo you want to join, and make sure you carefully read over a contract (and ideally retain a lawyer to go over your contract), but that was good advice before Nijisanji was unquestioningly outed as a black company.