For your TL;DR: Stop conflating authoritarian regimes with communism.
While communism as an ideology does not necessarily imply authoritarianism, the historical examples and implementations of communism have often been characterized by authoritarian practices. It is essential to distinguish between the principles of the ideology and the realities of its historical manifestations.
However, it is worth noting that certain aspects of capitalism, such as the concentration of wealth and power, can potentially create conditions that contribute to authoritarian tendencies. When wealth and resources become heavily concentrated in the hands of a few, it can lead to inequalities, exploitation, and a lack of accountability. In such situations, there is a risk that powerful individuals or corporations may exert undue influence over political processes and undermine democratic principles.
Furthermore, in some cases, authoritarian regimes have adopted capitalist economic policies while maintaining strict political control. These systems, often referred to as "authoritarian capitalism" or "state capitalism," feature elements of both capitalism and authoritarian governance. They may include limited political freedoms, restricted civil liberties, and limited checks and balances on the power of the state and its economic elites.
We must distinguish between the economic system of capitalism and communism within the political system in which they operate. While capitalism nor communism themselves do not inherently imply authoritarianism, the interplay between economic power, political influence, and the structure of governance can contribute to the emergence of authoritarian tendencies within these two systems.