“Finding a company willing to host your server or in the cloud” is trivial once you actually get serious about looking. There are entire companies whose only line of business is offering server space. They’ve been around for decades for decades and some have grown positively huge.

Some names to get you started:

Digital Ocean

Linode (now owned by Akami)

Host Papa (Canadian web hosting service that also offers server space).

There are also turnkey installers for lemmy, some tailored to specific hosting technologies.

The only way for corporations to take over the fediverse is through the inaction of those who prefer otherwise. Keeping in mind, of course, that it might turn out that the majority of people might actually flock to a Facebook-controlled instance. No big deal. Those of us who prefer to just kick around on the open internet will continue to do so.