I'm not sure if I completely understand what you're asking, but I use Coinbase to buy my crypto when I need to

I'm pretty sure you can buy crypto with fiat money using the decentralized open-source non-kyc application called Haveno

Are there any decent (Private or otherwise) payment portals that anyone could recommend, that allow customers to pay cash, but it could convert and deposit into a crypto wallet, preferably BTC on the fly, with as low fees as possible?

A bank and an exchange? Or some third party local cash to crypto sellers which has its own physical risks.

So you want a money laundering service?

I was wondering if there was something similar a few weeks back.

Basically I was wondering if there is a payment processing service like Paypal. It handels all the transactions on your businesses behalf, but the payments in cash from customers are converted to crypto and deposits into your crypto account/wallet.

I sometimes come across sellers only accepting payment in crypto and always wondered why not have a platform that converts cash automatically for buyers right on the sellers website. Takes away the "extra step" of having to convert to crypto on one's own.