Dual Monitors Not Working

I have recently built myself a new desktop machine. I put an AMD Ryzen 3 3200G (with Radeon Vega 8 graphics) on an Asrock B450M-HDV R4.0 motherboard. Everything I read before the build led me to believe that this combination should be able to provide HDMI, DVI, and VGA outputs concurrently. Each output works fine individually, but I can't seem to get more than one output to work at a time. When I check xrandr, no matter what I've tried, it only shows one output. I'm running MX Linux on that machine, in case that makes a difference.

I have tried copying, independently, 10-amdgpu.conf and 10-radeon.conf from /usr/share/X11/xorg.conf.d/ to /etc/X11/xorg.conf.d/, but neither of them worked. Both times I got only a blank screen with a flashing cursor in the upper left corner, instead of starting the GUI. I did check the output of inxi -G, and found that the amdgpu driver showed as "unloaded" when I tried to use it, but the radeon driver did not. The generated /etc/X11/xorg.conf was quite generic, and only called for the vesa driver. I tried substituting amdgpu and radeon there, but with the same disappointing results. I even tried to put together my own xorg.conf, with the monitor specs and such, but that didn't work either. I wasn't 100% certain of what I was doing with that, however. I tried to follow the examples I could find, but I kept feeling that there was something I just wasn't getting.

The output of uname -r is:
Code:4.19.0-1-amd64The output of lspci is:
Code:00:00.0 Host bridge: Advanced Micro Devices, Inc. [AMD] Device 15d0
00:00.2 IOMMU: Advanced Micro Devices, Inc. [AMD] Device 15d1
00:01.0 Host bridge: Advanced Micro Devices, Inc. [AMD] Device 1452
00:01.2 PCI bridge: Advanced Micro Devices, Inc. [AMD] Device 15d3
00:08.0 Host bridge: Advanced Micro Devices, Inc. [AMD] Device 1452
00:08.1 PCI bridge: Advanced Micro Devices, Inc. [AMD] Device 15db
00:08.2 PCI bridge: Advanced Micro Devices, Inc. [AMD] Device 15dc
00:14.0 SMBus: Advanced Micro Devices, Inc. [AMD] FCH SMBus Controller (rev 61)
00:14.3 ISA bridge: Advanced Micro Devices, Inc. [AMD] FCH LPC Bridge (rev 51)
00:18.0 Host bridge: Advanced Micro Devices, Inc. [AMD] Device 15e8
00:18.1 Host bridge: Advanced Micro Devices, Inc. [AMD] Device 15e9
00:18.2 Host bridge: Advanced Micro Devices, Inc. [AMD] Device 15ea
00:18.3 Host bridge: Advanced Micro Devices, Inc. [AMD] Device 15eb
00:18.4 Host bridge: Advanced Micro Devices, Inc. [AMD] Device 15ec
00:18.5 Host bridge: Advanced Micro Devices, Inc. [AMD] Device 15ed
00:18.6 Host bridge: Advanced Micro Devices, Inc. [AMD] Device 15ee
00:18.7 Host bridge: Advanced Micro Devices, Inc. [AMD] Device 15ef
01:00.0 USB controller: Advanced Micro Devices, Inc. [AMD] Device 43d5 (rev 01)
01:00.1 SATA controller: Advanced Micro Devices, Inc. [AMD] Device 43c8 (rev 01)
01:00.2 PCI bridge: Advanced Micro Devices, Inc. [AMD] Device 43c6 (rev 01)
02:00.0 PCI bridge: Advanced Micro Devices, Inc. [AMD] Device 43c7 (rev 01)
02:01.0 PCI bridge: Advanced Micro Devices, Inc. [AMD] Device 43c7 (rev 01)
02:04.0 PCI bridge: Advanced Micro Devices, Inc. [AMD] Device 43c7 (rev 01)
02:06.0 PCI bridge: Advanced Micro Devices, Inc. [AMD] Device 43c7 (rev 01)
02:07.0 PCI bridge: Advanced Micro Devices, Inc. [AMD] Device 43c7 (rev 01)
07:00.0 Ethernet controller: Realtek Semiconductor Co., Ltd. RTL8111/8168/8411 PCI Express Gigabit Ethernet Controller (rev 15)
08:00.0 VGA compatible controller: Advanced Micro Devices, Inc. [AMD/ATI] Device 15d8 (rev c9)
08:00.1 Audio device: Advanced Micro Devices, Inc. [AMD/ATI] Device 15de
08:00.2 Encryption controller: Advanced Micro Devices, Inc. [AMD] Device 15df
08:00.3 USB controller: Advanced Micro Devices, Inc. [AMD] Device 15e0
08:00.4 USB controller: Advanced Micro Devices, Inc. [AMD] Device 15e1
08:00.6 Audio device: Advanced Micro Devices, Inc. [AMD] Device 15e3
09:00.0 SATA controller: Advanced Micro Devices, Inc. [AMD] FCH SATA Controller [AHCI mode] (rev 61)Any and all help is greatly appreciated.