Is the FGC basically the chinese league? Why EDG and FPX are not playing in it? Or did they get a by to playoffs or whatever?
It's not the Chinese league. It's a separate third-party tournament that has been the main competition in China since 2021.
What you're seeing now is the qualifiers for Act 1. EDG and FPX are invited to the main event of Act 1 here: https://www.vlr.gg/event/1525/fgc-valorant-invitational-2023-act-1