Ipso facto it ceases to be a 'democracy'...or does it? Virtually every country calls itself a democracy of sorts. Definition is everything. China's "People's Democracy" is known as Communism in other places. American democracy is an oligarchic, capitalist duopoly, as are UK and Australia. Rule of and by the people (actually 'power' - kratos) uses a representation system to avoid being unwieldy, but even the first Greek democracy was limited to those of privilege and not the lower classes.
Social media and the 'digital revolution' has forever changed society in ways the Industrial Revolution could not. While the latter changed the means of production and made commodities more available, this promoted materialism. Social media on the other hand frames opinion, pushes agendas and disseminates propaganda in ways the MSM could not, with an exponential reach hitherto impossible. Diving into the ownership of TikTok ('TT'), it is surprising to find some of America's biggest billionaires are shareholders in Bytedance, the corporate owner of TikTok - for example, Steven Mnuchin, Trump supporter Kevin O’Leary, right-wing megadonor Bobby Kotick and Jeff Yass. Guess who would stand to benefit were TT to be sold? Those who would gain control would not be politicians. They would not be the ones who sit in the US Congress or Senate, and they would certainly not be elected. America's putative democracy would be overruled by a cartel of billionaires to whom politicians such as Trump would be beholden.
My view is the US democracy is already controlled, not necessarily just by authoritarian means, but by big capital which will do whatever it takes to ensure obscene wealth is perpetuated. Follow the money - it always works!