You could make an argument that Berkshire Hathaway is the largest M&A firm ever. But it's not really private equity (though it's not really public, either).
Dell's approach was actually more like the classic "taking a company private again", where you use public equity markets to grow big but keep control, then take it private at terms that don't really reward shareholders for the massive growth. This looks like the modern variety of PE capturing predictable revenues from a large, mature client base that can pay their fund the expected returns for the next 5-7 years. It's boring as hell and never means (a) a better product, or (b) a bigger pay-off for employees.
Having worked for a Silver Lake funded company (I originally called a startup, but that's not fair to say anymore for a private company that now makes billions), I can assure you that they don't take a back seat to how the company is ran (that's not to say they take a direct hands on approach, either).
In 2017, I joined a company that had been spun out of Ebay and bought by a PE firm. The firm invested a large amount of "growth capital" in the biz to transform the product from a software license to a cloud-based service. This transition not only increased our revenue exponentially but also gave us the ability to analyze data on how customers were using our product (prior to this, we had zero visibility into how customers used our on-prem product). Using this data, we were able to better serve our customers & partners and improve the overall experience of using the product. A few years later, we sold the company to a large company for a pretty penny (>$1B).
This is all definitely anecdata but, IMO, being backed by a PE firm forced us to focus on revenue (really EBITDA) alongside product growth. A mechanism that forced us to focus on the impacts of each product decision we made. I think this ultimately helped us keep a steady pulse on the market w/o chasing every shiny new trend that popped up.
(Maybe that's just a stupid rather than a serious question)