Used a slim EFI, successfully booted into the system and installed macOS. However, when I added the extra kexts back, the startup speed became significantly slower, looping error message "IOKit Daemon (kernelmanagerd) stall[0], (60s): 'PXSX' ", but eventually it would boot. Also, my wifi is not working, while Bluetooth is totally fine. I'm using a BCM94352z wireless card with BlueToolFixup.kext, BrcmFirmwareData.kext and BrcmPatchRAM3.kext, which seems to be the problem. I saw this post here,
however, the link provided in the answer that solved the problem isn't available any more. My full EFI is included here: https://drive.google.com/file/d/1Hxns_bCOCakwLRuYf2NnlAAbquQKF3vb/view?usp=sharing. Help is very appreciated!!!