You don't need to take it slow. I moved from Gmail to a private email that I manage about 5 years ago. I just put email auto reply on my Gmail saying that I've changed my email due to an onslaught of corporate spam. Spammers won't get the new one because they're using auto responders, but actual people will get the auto reply and start using your new email address. You can change your email associated with accounts as you log in, or you can just keep those on Google so that the accounts don't start spamming you on your new email too. The only drawback is that your account won't be in some big data database and some sign up processes that use services like Informatica might reject your email as invalid since they don't have a record of it. When that happens just use your Gmail and then update it later.

Nextcloud can be self hosted very cheaply, or you can find some hosted instances. There are applications that can encrypt cloud storage for some services. I would recommend just getting a NAS or a VPS and running nextcloud on it.

Pretty much any other cloud, OneDrive can do all that docs stuff if you need it.

Pro solution: buy a NAS, many of them do have online office suites (like, for example, Synology), and stop depending on the cloud in the first place.

There's proton drive...which i hasn't actually used. It looks like google drive, and there's a photo option, but so far I've only used the proton mail part.

I switched to Onedrive recently and it went pretty smoothly for me. Feels like trading ones evil for another, though.

Proton all the way. E-mail, calendar, contacts, Proton Drive, and VPN if you want it. You can use a custom domain for your e-mail address, as well. Photos are another story, though.