icloud issues

hi,

any help would be super appreciated!!!

i recently bought a new iphone SE 2020, and i have a macbook air 2012.

i used to have an iphone 5c, but i took it off my icloud account.

but now my messages no longer sync, my contacts dont either,

and plus, somehow apple seems to think my macbook IS my other device, because every time i come here to this forum and sign in via my macbook, a message pops up saying my "apple id is being used to sign in to a new device, enter this verification code to sign in, and i have to enter the code on my macbook right on my macbook's blanks that appear.

also, i have this persistent notice on my ihpone's settings asking me to "update apple ID settings", then i AGAIN enter my password, but then it always AGAIN asks me to "approve this iPhone": "go to one of your other devices signed in to iCloud to approve this iphone."

BUT, all it does is say "waiting for approval" and shows that spinning wheel, and when i go to my macbook there is NOWHERE i can find to "approve the iphone" FROM!

i have tried going into my macbook settings/icloud but nothing is in there waiting to be approved.

i can generate a verification code, but there is no where to put it!

and when on my iphone i try hitting that "cant approve this iphone?" message, these 2 choices pop up:

reset encrypted data

or

cancel.

i finally out of desperation tried that "reset encrypted data",

' but it did not fix anything!

when i go to my online icloud account, i see both my macbook and my iphone se 2020 there and signed in.

I have also tried signing out of my icloud on both devices, turning the devices off then back on, and re-signing in.

I also tried unchecking, then re-checking, the icloud messages and contacts.

No luck!

im at my wit's end.

What to do???