In the Orthodox Church, there is a widespread practice of infant baptism in the presence of godparents. In addition, some adults also wish to have godparents at the time of receiving the sacrament.
The presence of godparents during the baptism of infants is due to the fact that the child himself cannot yet openly express his faith in Christ, unite with God, reject Satan and all his works. That is why the godparents do it for the baby. The godparents themselves take responsibility for raising the child in the Orthodox faith. They testify before God for the baby. The situation is different with the baptism of adults.
An adult may well make decisions about joining the Church. Adults, being in a clear mind and adequate condition, themselves testify to their faith, combine with God and give a "promise" to try to live in accordance with the divine commandments. That is why the baptism of adults is performed without godparents. It turns out that the "function" of testifying to God for a person does not matter when it comes to baptizing adults.
It is worth mentioning, however, that some adults still wish to have godparents. The Church cannot give a ban on this, but, at the same time, the person being baptized himself needs to understand that there is no need for such practice. Adults often choose friends as godparents. The reason for this can be considered not so much religious as domestic. Some consider this practice to be an affirmation of friendship.
Thus, we can say that the presence of godparents during the baptism of adults is not necessary. However, those who strongly desire it can choose their godparents. This practice does not harm the person being baptized, but it also does not carry any special meaning, turning the presence of godparents into an ordinary formality.