Unfortunately the best option is to not use these type of sites, especially if they are asking for identification or personal information. The web worked well enough for years with people just using usernames.

Personally when friends or family ask me why I not on a specific platform my response is usually because of the algorithmic feeds. This gets the conversation going where sometimes I get someone to actually switch.

The second best option if you really need to lurk on sites like this is using your "porn star name". If you happen to know someone that makes fake ids, get one made using your alternative online identity and use that for when a website ask for it. You might even be able to use a AI image generator to produce something, or depending on your Photoshop skills you could go that route.