In the interests of trying to add something new to the conversation- I just finished a poly sci book called The Economic Effects of Constitutions, which argues that presidential systems in general are less regulated, have lower taxes, and have a smaller welfare state than parliamentary systems. As it relates to regulating Big Tech, we can compare the US and Europe here. The book says that the multiple centers of power in presidential systems, especially bicameral ones, means that there are many separate powerful groups that must be appeased to pass even popular legislation with a consensus behind it. Here, a separately elected President has to grapple with a separately elected House, plus a Senate where two-thirds of the members were elected at a completely different time. Plus, party discipline is weaker in presidential systems, so he can't just whip his party to fall in line (most famously with Sinemanchin recently). 3rd party lobbying is then more powerful with weaker parties and separately elected reps who must cater to the marginal voter or power group in their district. Powerful interest groups are more powerful in a presidency!

Seeing as there's a broad but not ultra-strong consensus in both parties to Do Something with Big Tech, in a coalition parliamentary system a bill would've likely already passed. Whether you think that's good or bad is an exercise left up the reader, just wanted to introduce a new perspective :)