I don't want anything stored in the cloud. My goal is to NOT be logged into anything nor have anything stored where I cannot get to it in flight (or any other situation where internet is not available).
ForeFlight stores everything locally.
FWIW, Apple doesn't automatically store everything in the cloud the way other vendors tend to. They actually ask you first, with a prompt, and they let you say no.
I think part of the reason they pester you to log into your Apple account is for security. Once you're logged in, nobody else can wipe the device clean without your AppleID and password. If you don't log in, someone else can swipe it, do a factory reset, and easily sell it.
In addition, there are some iCloud services that are worth enabling, such as Find My in case you lose it, iCloud Keychain if you have any other Apple devices (so that passwords you use on one are available on the others), those are the big ones to me.
Here's some things you should configure (or ensure are configured) for an iPad that you're going to be using as an EFB:
1) Turn off automatic app updates to ensure it doesn't decide to update when you're on the takeoff roll... Settings -> Apps -> App Store -> App Updates
2) Turn off automatic iOS updates, wait for ForeFlight to test them and send out the "OK to install" email and then update manually. Settings -> General -> Software Update - Automatic Updates. (Automatic downloads can be turned on.)
3) If it asks you if you'd like to offload apps to save space, say no. To check on this setting, Settings -> Apps -> App Store -> Offload Unused Apps

I wasn't making a comment on apple as much as the music industry, and I'll stand by my stereotype. Pun maybe intended.
Macs have LONG been the choice of creative types, because Apple has leaned into that market since the beginning. Whereas office type stuff and specialty programs have usually been on Windows, anything dealing with graphics, design, audio, video, etc, Macs have always been the first choice.