MAKE INSTALLER
createinstallmedia to an empty HFS+ partition
edit the partition's "Library/Preferences/SystemConfiguration/com.apple.Boot.plist"
add "-no_compat_check -v keepsyms=1" to "Kernel Flags"
convert "InstallESD.dmg" to read/write
replace "OSInstall.mpkg" from 10.13.6

INSTALL
boot from it and install to an empty HFS+ partition (will convert APFS)
after (\), fix the target volume's "macOS Install Data/Locked Files/Boot Files/com.apple.Boot.plist"
reboot and finish install
after (\) again, mount "Preboot"
fix ".../Library/Preferences/SystemConfiguration/com.apple.Boot.plist"

FIX PENRYN KP
delete "/System/Library/UserEventPlugins/com.apple.telemetry.plugin"

FIX HANG
IOHIDFamily.kext
replace "_isSingleUser" with:
mov rax,0x1
ret
TODO: a better fix

SOUND
from 10.13.6:
AppleHDA.kext

WIFI
from 10.14.5:
IO80211Family.kext

ETHERNET
from 10.14.5:
IONetworkingFamily.kext/Contents/PlugIns/nvenet.kext

GRAPHICS
from 10.13.6:
NVDANV50HalTesla.kext
NVDAResmanTesla.kext
0x1ea59a-0x1ea5b3: nop
hex edit VSLGestalt --> IOLockLock
GeForceTesla.kext
0x5cf9f: nop
GeForceGA.bundle
GeForceTeslaVADriver.bundle
GeForceTeslaGLDriver.bundle
from 10.14.3:
GPUSupport.framework
OpenGL.framework
current:
IOSurface.kext
0xd59c-0xd5b0 nop
0xd610-0xd621 nop

SKYLIGHT
put in Input:
from 10.14.5:
SkyLight.framework
from 10.14.4:
CoreDisplay.framework
run "Build.tool"
install from Output

REBUILD PRELINKEDKERNEL
disable rootless
volumeName=Catalina
sudo chown -R root:wheel /Volumes/$volumeName/System/Library/Extensions
sudo chmod -R 755 /Volumes/$volumeName/System/Library/Extensions
sudo kextcache -prelinked-kernel /Volumes/$volumeName/System/Library/PrelinkedKernels/prelinkedkernel -kernel /Volumes/$volumeName/System/Library/Kernels/kernel /Volumes/$volumeName/System/Library/Extensions

ENABLE SUBPIXEL RENDERING GLOBALLY FOR A USER
defaults write -g CGFontRenderingFontSmoothingDisabled -bool false
RE-DISABLE FOR AN APP:
defaults write com.app.name CGFontRenderingFontSmoothingDisabled -bool true