You're missing the most crucial element of all, the class that makes up the majority of society should be the ones running and controlling the state and the commanding heights of the economy. If you have a small ruling class, as it exists in every single capitalist country, this class will bend whatever democratic institutions exist on paper to suit their whims. Any "independent media" will be flooded with media dominated by them. Education will be twisted to value capitalism. It isn't that "crony capitalism" eroded democracy, it's that bourgeois democracy has never and can never represent the working class.

For democracy to even exist, the workers must run and own the state and the commanding heights of the economy at a minimum.

You also need a fully open and transparent government, any information being classified top secret or anything of the sort means you cannot have a democracy. No secrets can be allowed, ever. And really the only way to reasonably guarantee stuff like that is to make officials surrender all privacy related rights for life, just permanent publicly open insight into every aspect of your life, past, present, and future if you want to pursue office. I'd argue for attaching 24/7 live streamed cameras to them during their time in office as well. Obviously this would only currently work for rich countries with obscene military expenditures, like the US, but if the big guys were to do it then it would eventually be safe enough for the rest of them.