Company A raises prices and reports record quarterly profits. Company B is aware of this because both the price raising and quarterly profit report for Company A are public. Company B raises prices too so that they can get also get more profit. Company C either does the same thing, or there is no company C because rubber stamped mergers and acquisitions for decades have allowed a handful of companies to dominate every industry, sometimes multiple industries.

None of this is a conspiracy. It's Econ 101 level "how things work."

You keep saying "across the entire economy" but not every sector of the economy was equally affected.

Also, there is good competition in some sectors (where it's easy and cheap to produce the product and the supply chain isn't very complicated) and definitely not others. Look at gas prices, which were involved in a lot of the inflation and its secondary effects. You can save a few cents here or there by shopping around, but otherwise the price is relatively similar (and relatively high) everywhere you look in an area.

In some sectors there's basically no competition at all. My Internet bill rose, do you think that's because of the money supply or because there's essentially no competition amongst telecom providers basically anywhere in the country?

A huge part of inflation is still rising rental rates. In my city about six companies own most of the large apartment buildings that people live in. Something tells me they'd have no problems raising rents between the six of them just because they easily can.