I have earnings in 2022 from OnlyFans, however, I have not cashed out those earnings. OnlyFans has informed me that, since the funds are still there and unrealized, they will not be providing a 1099. As they will not be reporting, is the unrealized income something that should be reported/taxed
Yes, you will need to report this money as income, even though you have not "cashed out" the money is in your account and available to you. It is similar to having a bank account. You have the money in the account, it is still your money. You do not have to do anything to earn it. You do not need to do anything other than withdraw it to get access to it.
Whether or not they give you a 1099, has no bearing on whether or not the income is taxable.
You are required to report all your taxable income, even if you don't receive reporting paperwork.
Income is taxed when you receive it. In this case, the doctrine of "constructive receipt" means you received the money when it was available for you to draw, even if you didn't actually draw it.