Catalina fresh install - can't launch installer - Service exited with abnormal code: 1

I'm attempting to do a completely fresh install of Catalina using the latest version of UniBeast, and when I start up from the USB installer it does not finish launching. Here's what I get:

Endpoint has been activated through legacy launch(3) APIs. Please switch to XPC or bootstrap_check_in(): com.apple.bsd.dlrhelper
Service exited with abnormal code: 1

(More detail in the attachment)

I have tried this with two different video cards (1070Ti & RX580), and the message is identical. In boot arguments I have tried toggling both Nvidia settings, which made no difference. In my bios I have VT-d disabled, Secure Boot Mode disabled, IO Serial Port disabled, XHCI Handoff enabled. I've tried the USB installer in 3 different ports.

Thoughts?

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Motherboard: ASRock Z370 Killer SLI/ac
CPU: Intel Core i7-8700K

Graphics (tried both separately):
MSI Radeon RX 580
EVGA GeForce GTX 1070 Ti

My High Sierra installation has been working fine with the 1070 btw.

https://preview.redd.it/pb6ophz2pbz51.jpg?width=4032&format=pjpg&auto=webp&s=960979395b582107ad1499fed8c168c937dcc40b