Ryzen 2400G and two monitors/screens

This APU is on a ASUS ROG Strix X570-I Gaming mini-itx board that has HDMI and Display Port outputs. My LG-55UF7600-UJ wide screen LED TV and LG 27EA33 27" monitor have HDMI inputs, no DP. So, I use a DP-HDMI adapter and HDMI cable. This has been working on the DP output of an ASUS Z170i motherboard with the on-chip graphics of an Intel i5-6500 CPU to the TV but is a bad experience on the x570i.
I set the monitor as primary display in systemsettings 5 but it seems to not have any importance: most apps open on the TV. Thinking it might be the DP output was taking precedence, I switched it to the monitor with no change (except the boot screen with grub graphical menu only shows up on the DP connection, the HDMI-connected screen only turns on when boot messages have started to display). If I try to "move" the app from TV to monitor, it will move but a dragged-out remnant of the window is left on the TV and is unresponsive, cannot be closed. (Dragged-out like fanned-out playing cards, many overlapping images)
I am using up-to-date MGA7 with Plasma desktop. It had been all set up with icons and Apps added to the desktop (Desktop layout) from the menu etc. When I added the TV, the icons disappeared. I got them back after a series of deleting xorg.conf, reconfiguring displays in kcontrol, and/or running an "update" netinstall in order to run through the wizards.
At one time Drakx provided an option for display on a second monitor but it's no more. Does anyone recognize a strategy to try?
Thanks.
I set the monitor as primary display in systemsettings 5 but it seems to not have any importance: most apps open on the TV. Thinking it might be the DP output was taking precedence, I switched it to the monitor with no change (except the boot screen with grub graphical menu only shows up on the DP connection, the HDMI-connected screen only turns on when boot messages have started to display). If I try to "move" the app from TV to monitor, it will move but a dragged-out remnant of the window is left on the TV and is unresponsive, cannot be closed. (Dragged-out like fanned-out playing cards, many overlapping images)
I am using up-to-date MGA7 with Plasma desktop. It had been all set up with icons and Apps added to the desktop (Desktop layout) from the menu etc. When I added the TV, the icons disappeared. I got them back after a series of deleting xorg.conf, reconfiguring displays in kcontrol, and/or running an "update" netinstall in order to run through the wizards.
At one time Drakx provided an option for display on a second monitor but it's no more. Does anyone recognize a strategy to try?
Thanks.