Another possible way where many people will believe it is from him is signing a message from that his dormant addresses saying he published so and so information and that’s his/her identity. It is even the most believable thing because we all know only Satoshi has access to the private keys to those addresses
You are right here because signing a message with the wallet will call attention that Satoshi is back but for him to do such, he must have prepared or worked other modalities to escape the government tracking him and besides if he can invent bitcoin which the government can not control, he can also avoid the government from tracking him but in all, Satoshi seems not to be bothered about revealing his identity so soonest because he himslef knows the implication of such move and mind you he is not a dommy to have been able to invent such technology and not have other ways to be able to get a back up wallet to accumulate or mine bitcoin aside the genesis block. Satoshi is somewhere right now chilling and enjoying his bitcoin which he had mined with his other wallets which you never can tell so what is the point bringing up this issue of Satoshi revealing his identity.