You might want to check out the Bigme HiBreak phones, they're basically low-mid Android phones with e-ink screens. They work perfectly well for the dull functional things expected of a phone, while rendering all the addictive and spammy patterns pretty ineffective. I've found my one very useful as an intermediate step between a dumbphone and a traditional smartphone.

Why do you need a flip phone though? Just use your smartphone as you would a flip phone. Don't install ticktok. Problem solved.

I tried out dumb.co. Their flip phone supports maps, MFA, Uber, imessage/call forwarding.

I unfortunately didn't use it nearly as much as I thought I would have. It's also significantly bulkier in my pocket than my 13 mini. Loved the idea though.