even though the transaction shows as confirmed the receiver has not received the funds.
That isn't possible with Bitcoin. As soon as the transaction is confirmed, the recipient has received the funds. Even if their computer was turned off the whole time. Even if they previously set fire to, their computer and everything they ever owned or touched was already atomised in a nuclear explosion last Wednesday. When receiving money, no action whatsoever is needed by the recipient or their wallet. They or their ashen or vaporous remains now have that money.
Remember, wallets don't contain money. Money doesn't travel anywhereMoney doesn't travel anywhere. A transaction in the blockchain is a record of change of control over some amount of money. That is all there is. The blockchain is the only truth.
If the address is correct, either the recipient is mistaken or lyingor lying.
If the receiver's wallet is offline, broken or unsynchronised, that is their problem not yours. They still have the money, no-one else.
If the receiver uses a custodial wallet, the custodian has the money. That is the receiver's problem, not yours.