Communication on these platforms is public, protected speech just as it was on your street corner. And commerce on these platforms should be protected in the same way as commerce on the street. Government is government and needs to be restrained in all of its forms or it will become a force of authoritarianism that either works on it's own or within the machinations of current government.
The EU is going the right direction with the Digital Markets Act. This act implicitly suggests that these gatekeepers have a special status though it does not outright call them what they are - governments. Speech protection should also be there as it is in all functional, modern governments. As should transparent legal process. Governments should have representation from their constituency.
Big tech is government.