The character created on PSN can not be used on PC

Today, I linked my PSN and Steam accounts, but I am unable to use the character created on PSN on the PC version.

Here’s what we know so far:

Both PSN and PC servers are set to the same Japan region.

If a new character is created on the PC version, it can join the instance.
(If the issue is related to network security, then the new character should also be unable to join the instance.)

Could you kindly provide any guidance or solutions?