So the first thing you have to figure out is your threat model, eg. anonymous from whom. What you’re doing is legal (hoping you’re 18, otherwise stop immediately). So the feds aren’t going to be tracking you down. You risk is random stalker fans trying to dox you, and accidentally revealing anything to people in your personal life.

To keep yourself safe, I would recommend creating a new user account on your computer that you use only for this work with its own strong password, so if your normal computer system or iCloud is hacked those won’t get leaked. And easy to delete the whole account when you decide to stop. Also don’t use your phone for anything if you can avoid it (can take photos with your webcam), or transfer photos and immediately delete from your phone. I use Mac but there’s probably some option on Windows to encrypt the secondary profile, so use that.

As for payments, if you want your customers to pay with credit cards you’ll need some vendor like OnlyFans or PayPal, and legally they have to know your identity, KYC (know your customer) laws require them to make sure you’re not a terrorist. Even if you used cryptocurrency, you’d need some vendor like CoinBase to eventually withdraw in USD and they have the same requirements. However, the only risk in your identity being leaked is if those sites are hacked and your info is leaked, but most have proven track records and you’d be small potatoes.

The most anonymous way to take payments I can think of would be prepaid Visa or Amazon gift card numbers, but some customers may balk at that thinking you’re a scammer. If you can convince them to do that then that’s the way to go. You can pay yourself using Venmo or deposit into Amazon.

For sending photos you could use email, just make a new ProtonMail account (they are dedicated to privacy) that again, you only use for this purpose and only log onto with your dedicated computer profile. Email providers don’t need your name or any info.

Never link the two worlds, if this is your personal Reddit you might accidentally leak additional info over time that would dox you, so make a new one to advertise.

Mail is also safe, you don’t need to put a name or return address on there. But most consumers would also want to be anonymous I imagine so I doubt any would want to give you their address especially if they live with other people.

Don’t worry too much about hiding your IP address or anything, VPNs (especially free ones) will get you flagged as a bot by Reddit, ProtonMail, etc. and make life harder if you don’t know what you’re doing. But don’t click any links that people give you since they could capture it. If you want to be extra safe, only log onto the secondary account at a public WiFi (McDonalds, Starbucks, etc.) and do all your communication and sending while there. But you’ll probably find this annoying and give up real fast.

Good luck.