99.99% of my buyers, have no idea what bitcoin is.. so using a bitcoin payment gateway is useless since they don't own bitcoins already. Is there maybe a very simple way for users to buy bitcoins and get them sent to me instantly or something similar?
It seems unlikely that anything would work that way around.
Bitpay lets you accept Bitcoin and can deposit directly into your bank account, but your users would still have to go through the process of buying Bitcoin (and as you point out, it's just a gateway).
The closest you could get is using
Coinbase as a gateway, and suggest buying Bitcoin through their exchange. Then you could accept a transaction from them, or even one of Coinbase's offchain transactions and then withdraw the coins to your own wallet (not that I particularly approve of that centralisation).
PayPal services are hard to deal with due to the risk of chargeback fraud, and credit cards are equally annoying, so they would have to use a proper exchange like Coinbase or or trade P2P with LocalBitcoins.