1. Bring back those laws requiring fairness of media representation.
2. Force standardized disclosure of sponsored content of any type (total, segments, placement). Many countries already do this. Standardized = big, high contrast "Ad" sign in the corner with mandatory size proportional to content size.
3. Mandate providing sources.
4. Treat all influencers with an audience above NNN followers (10000?) as mass media.
5. Require that widely shared content is fact checked and that fact checking is automatically included while sharing and provide recourse for fact checking up to the legal system.
6. For sensitive topics (politics, primarily) require AML and KYC disclosures of funding, primarily to find foreign funding sources and propaganda.
However, you know, vested interests, the bane of humanity.