An exchange which lets you buy BTC via various payment methods. One example of such a site is Bisq, check their Fiat Payment Methods.
Basically any DEX will do as long as it provides the desired payment method.
As for withdrawing the BTC from your PayPal account to another wallet, according to https://news.bitcoin.com/bitcoin-paypal-crypto-services/ that's not possible.
Specifically it states that you won't be provided with a private key. As a consequence those BTC technically aren't yours to begin with.