You will need to use Weston + XWayland so that you can use your X11 GTK application. NXP will not support X11 directly in iMX8, only through XWayland.
Inside the weston container with XWayland enable, try to launch your own X11 GTK application: TorizonOS 6.5 Running a Qt app linked xcb under wayland - #6 by leon.tx
Here you can see how to enable XWayland: Weston - ArchWiki
What is the BSP version you are using?