That's not what that means. In the context it is about forgiving others who sin against us individually. I can forgive you if you wronged me somehow and you can choose to forgive me, but sins against God can only be forgiven by God. When Jesus told them this not all apostles were there (at least Thomas was absent) and this was prior to Pentecost and baptism of the Holy Spirit. Often Jesus said they should forgive those who harm them. Matthew 18:21-22
Then came Peter to him, and said, Lord, how oft shall my brother sin against me, and I forgive him? till seven times? 22 Jesus saith unto him, I say not unto thee, Until seven times: but, Until seventy times seven.
the context of the passage is not Matthew 18:21-22 and it's not even related. when we mix verses like this together we develop a type of proof text to simply say what you want it to say and it is irresponsible way of biblical interpretation. Each verse has a context and the most productive meaning is from the immediate context and then it can begin to work outwardly to perhaps get broader meanings but never to change only to agree.
The context of John 20:23 starts with Jesus making a post-resurrection appearance to the disciples, affirming his mission from the Father and passing that on to the disciples by breathing on them the Holy Spirit. And this is what sets up this authority to grant forgiveness.
The message and mission of Christ is to spread the gospel and the gospel brings belief which gives forgiveness. There is definitely an authority being granted here that is implicitly connected with the breathing of the Holy Spirit. Personal forgiveness, however, requires no special authority except for that you wronged in some way; anyone may forgive another that has wronged them regardless of their faith in Christ.
This forgiveness here is however connected with the aforementioned breathing the Holy Spirit. To me, this is the commissioning that we see in Mat 28/Mark 16/Luke 24 as it's a post-resurrection commissioning and fits the contexts synoptically.
Synoptically I would say the context may be developed as follows:
Matthew 28:18-19
“All authority in heaven and on earth has been given to me. Therefore go and make disciples of all nations, baptizing them in the name of the Father and of the Son and of the Holy Spirit, and teaching them to obey everything I have commanded you. And surely I am with you always, to the very end of the age.”
Mark 16:15-18
“Go into all the world and preach the gospel to all creation. Whoever believes and is baptized will be saved, but whoever does not believe will be condemned. And these signs will accompany those who believe: In my name they will drive out demons; they will speak in new tongues; they will pick up snakes with their hands; and when they drink deadly poison, it will not hurt them at all; they will place their hands on sick people, and they will get well.”
Luke 24:45-49
Then he opened their minds so they could understand the Scriptures. He told them, “This is what is written: The Messiah will suffer and rise from the dead on the third day, and repentance for the forgiveness of sins will be preached in his name to all nations, beginning at Jerusalem. You are witnesses of these things. I am going to send you what my Father has promised; but stay in the city until you have been clothed with power from on high.”
John 20:21-23
“Peace be with you! As the Father has sent me, I am sending you.”And with that he breathed on them and said, “Receive the Holy Spirit. If you forgive anyone’s sins, their sins are forgiven; if you do not forgive them, they are not forgiven.”
You may disagree with the synoptic reconciliation but what is consistent in these passages is that they are all post-resurrection commissioning that passes authority on to the disciples and even if all are separate events they are all commissions and may and should be grouped together. Jesus breathes the Holy Spirit in John and in Luke he opens their eyes. In Mark, he gives him supernatural endowment which is implicit of the Holy Spirit and in Matthew, he affirms his own commission and passes on to them which again may be argued implicit of the Holy Spirit.
I would suggest at the heart of the passage is about a sending out with power and authority, by the endowment of the Holy Spirit, to spread the gospel (inclusive forgiveness).