After installing xrdp and xserver-xorg-video-dummy, I can connect via mstsc and ssh, but the monitor stays at the Ubuntu boot screen?

The graphics card in this machine is an Nvidia Quadro P4000.

When I use nvidia-smi, the output is

The steps I did are shown below：

1. install vino
2. install dconf_editor
3. install xmlstartlet
4. install xrdp
5. install xserver-xorg-video-dummy-hwe

Then I made the following settings:

config xrdp:

dconf write /org/gnome/desktop/remote-access/enabled true
dconf write /org/gnome/desktop/remote-access/prompt-enabled false
dconf write /org/gnome/desktop/remote-access/require-encryption false

The following has been added to the file /usr/share/glib-2.0/schemas/org.gnome.Vino.gschema.xml:

Changed the contents of the file /usr/share/glib-2.0/schemas/org.gnome.Vino.gschema.xml to:

Set up automatic user login by adding two lines to the file /etc/gdm3/custom.conf:

AutomaticLoginEnable = true
AutomaticLogin = user1

Adding vino to the bootloader:

I created a file /home/user1/.config/autostart/vino.desktop, the contents of this file are as follows:

[Desktop Entry]
Type=Application
Exec="/usr/lib/vino/vino-server"

Configuring a virtual monitor:

Add the following to this file /usr/share/X11/xorg.conf.d/xorg.conf:

After completing these configurations, I restarted the computer and it was able to log in via ssh and mstsc remote desktop connection. However, after connecting the monitor directly to the machine, the monitor stays at the ubuntu boot screen and I can't access the system. How can I solve this problem?