Update: my build is totally stable with Mojave 10.14.2, Macmini8,1 SMBIOS, HD630 with ig-platform-id 0x3E9B0007, and 4K monitor connected via DisplayPort. I removed the Radeon GPU to use in another build, and discovered that it works better without it sort of by accident.
In that configuration when I booted with the same monitor connected via HDMI then I got nothing on the display after it initialized graphics (2/3 through the boot bar), but I didn't troubleshoot since it worked fine via DisplayPort and the monitor supports both.
Update 2: Might have solved the stability with the Radeon GPU. My similar machine is stable with the RX580 on 10.14.2 if I boot with Clover 4701, Macmini8,1 SMBIOS, no ACPI patches in config.plist, inject Intel false, ig-platform-id 0x3E920003, current versions of FakeSMC, Lilu, WhateverGreen, AppleALC, and IntelMausiEthernet. I believe I have iGPU multi-monitor enabled in BIOS, and definitely have primary set to PCIe and monitor attached to the RX580. Still need to check that it's actually getting good accelerated graphics performance, though. (Might be worth trying with iMac18,3 SMBIOS as well.)
Note that I had to build the boot USB by hand to get the right Clover, config.plist, and kexts.
Also this is with the monitor attached via DisplayPort. This one has an HDMI-only monitor (TV, really), so I'm using a DP-to-HDMI dongle.
Update 3: I've updated the procedure in the first post to reflect everything I learned on the 10.14.2 installation, and it's now got the integrated graphics procedure. My other guide for the Z390 version of this board will have the RX 580 procedure.
@Snowpro I don't think VGA is supported. But as noted I had trouble with HDMI. If you're in the OS at all, I think you should use this procedure to get HDMI working, and then connect your monitor to the HDMI port with a DVI-to-HDMI adapter.
Most likely it is a USB problem. If you do a regular verbose boot and wait a while, see if it goes to the "prohibited" sign, and try to see if the text at the very bottom of the screen says something like "Still waiting on root device". Often the text gets garbled, but you might be able to make out whether that's the message.
Another clue to a USB problem is if the scrolling text at some point says something along the lines of "too many USB devices, not creating the remaining ones".
If that's the problem, you'd be able to complete the installation from a USB 2 thumb drive but not a USB 3 one.
Normally UniBeast creates an installation with the correct settings to avoid this, except they keep changing, so UniBeast might be putting the wrong patch in config.plist on the thumb drive if you're using a newer release of macOS than the one at the time it was built. Here's one for 10.14.1 that I think might work for 10.14.2 as well (this post also has the older 10.14.0 one, so you could verify if that's what's in your config.plist):