Are you using it to frequently communicate with people or mainly just to sign up for services? If the former, you may be better off using a phone that supports iMessage or Google Messages (depending on what’s more popular in your area) so you can have end-to-end encrypted texts so long as others won’t communicate with you over a secure messenger like Signal.
Option 2 is definitely a great option and you could ask the GrapheneOS forum regarding your concern. I could understand wanting to avoid social media but ideally you’d be able to have enough self-control to avoid it if you go that route. There are tricks like setting your screen to grayscale to make it less appealing. Though I don’t want to downplay anything if you had some sort of addiction. If that’s the case, perhaps option 5 is the way to go.
ONLYOFFICE or LibreOffice should work mostly fine, if not you could also try Microsoft Word over WinApps. If that seems too complicated or still doesn’t work for you then I’d give in and go for either a MacBook or iPad depending on how portable you want your device to be. From what I heard (not personal experience), MacBooks are less restrictive than iPads and therefore sorta give you a bit more freedom to protect your privacy from Apple a bit more. You might wanna skim some privacy tutorials such as any guides Techlore has for both Mac and iOS/iPadOS to get an idea of what I mean.