Using Microsoft products to avoid feeding megacorps would be a strange strategy.

Most of the fictional dystopia center around a single mega-corp not mega-corps... Thus if you have 3 or 4 Mega Corps that would be preferred to a single monopolistic Mega-Corp.

Do you have any book recommendations?

Dune's CHOAM corporation is a great example. Ownership in choam is synonyms with power and wealth. All political maneuvering is based on gaining or keeping control in choam corporation.

For "receiving end" perspectives, watch Blade Runner (the old one) or Altered Carbon. The Expanse probbly qualifies too. For books, Peter Hamilton incorporates different mega-corps in his universe but it's not the main object. Special mention to the Void Trilogy's Commonwealth.

The Expanse's high-political scene is best described by the balance of powerful sovereigns, and how that changes over time. Companies have a lot of power, but that power is primarily expressed by influence in governments. A company gets mining rights from a U.N. charter by influence. Then the company expects the U.N. military to defend those mining rights. Sometimes the company influences the goverment and sometimes the goverment influences the company. The big exception to this is the O.P.A. which always tends centralize power around Tycho.

Altered Carbon also uses goverment as the primary seat of power. United Nations Envoy Corps are primarily a reskinning of Dune's Sardaukar, the powerful super soldiers that enforce the rule of law out of fear. There are very powerful corporations, especially those discussed in the first book, but their power is again through the influence of government, and goverment has the authority to act independently.

This is in comparison to a true mega-corp like Final Fantasy 7's Shinra Corporation, where all power exists within the company. Shinra can destroy 1/8th of the capitol city with no repercussions, and there is no significant economic activity outside of the company.

I wouldn't throw someone into the deep end of corporatism based on where this thread started ;) I figured the implicitness of my examples' corps' power fits better as an illustration of the potential short term future.

Yours is a terrifying endgame, but it feels (to me) quite far removed from what we should look out for before it's too late.