It did not work unfortunately , i was still stuck on the same error stall
=========
After a bit of work, I managed to get it work. Posting in Case anyone has the same build as me and problem.
1.https://www.tonymacx86.com/threads/success-gigabyte-designare-z390-thunderbolt-3-i7-9700k-amd-rx-580.267551/post-2033519
I used this instead of osxaptiofix2000, which is said to be able to cause damage over the long term. The kexts completely solved my memory problem.
2. I kept the FakeID for IntelGFX (0x12345678) as well as the ig-platform-id (0x3E910003) for Intel graphics 630. Without this, my installer booted to a black screen .