Can the evil fee come later? When the user must have signed in, start learning and building the account, maybe before the user joins a signature campaign, bounty campaign or do business, he would have to pay the evil fee.
Evil fee of an IP address already is calculated by the forum before you make your account. Your latest registration attempt only can make the evil score worse a little bit.
I don't understand your implication (the italicized part), what does it mean? Evil fee, if required, would be required instantly after you register your account and log in. It does not relate to your account use cases. Signature campaign, bounty, scam, spam, etc., all of such don't trigger evil fee on your account. Such activities only trigger your account ban (temporary or permanent) or negative trust, feedback, active flag on your account.
By this time, he will be knowledgeable on how to make the payments
It's your assumption only. People can know how to do Bitcoin or crypto transactions before they join the forum.