Democracy is about balancing the needs of everyone, and that includes the corporate too. Regulatory bodies should have the necessary independence to hold regular discussions with the stakeholders (the executive, the corporates and the people) so that appropriate regulations can be drafted and more importantly fairly enforced.
It is in the nature of corporate to vie for power with the sovereign and thus in a democracy it is very much necessary to ensure that the corporate never gain gain an upper hand to do so. Regulations can definitely help with this. But ultimately it all about finding the right balance as hurting the corporates too is not the aim and in the best interest of a nation.
It is very abstract. You constantly talk about "the need of regulations" but don't get to specifics. You hope that by hiding in complexity under some abstract body things will work out. In reality, those "regulatory bodies with necessary independence to balance the needs of everyone" will be undeniably influenced by interests groups and shaped by the very people you want to avoid having too much power. Worse still, they get to be put in this position of power indirectly and out of reach from people to express their will through vote or elections.
No matter how much you talk, at the end of the day we all should be asking ourselves what are the things that we want to "regulate" and make it the systems as clear as possible to avoid regulatory traps.
Here is my proposal for a system that can control the abuse of power by corporate entities and at the same time avoid this trap of believing that "regulations" are magic dust that makes anything better:
1. Put a hard cap on the headcount of a corporation. Any company that gets past a certain size (say a few hundred employees) has to be split up by the end of the fiscal year.
2. No single person can be a board member or manager at more than one corporation. No subsidiaries shenanigans, no shell corporations, no "holdings". People and companies can have investments anywhere they want, but these should grant them any executive control over the board.
3. Governments must never bail out a company. If no company is "too big to fail", there are no systemic risk and bail-outs are not required.
That is it. By limiting corporations by size, you avoid any single entity to dominate the space, you promote healthy competition, you avoid systemic risks, you avoid rampant inequality and corruption, we don't get lost in a sea of abstractions and we avoid the hell of regulatory capture. We might lose the "benefit" of economies of scale and we will never see a "Unicorn-style startup" and we will never be talking about "FAANG" again, but I think that would be a good thing overall.