Ok some update following command worked and i saw the Lomiri Screen and the panel displayed for a small time

$Xephyr :5 -screen 1280x720 -extension MIT-SHM & sudo schroot -c trixie-amd64-sbuild -u root --directory=/root -- bash -c " mkdir -p /tmp/runtime-root && chmod 700 /tmp/runtime-root export DISPLAY=:5 export XDG_RUNTIME_DIR=/tmp/runtime-root export LIBGL_ALWAYS_SOFTWARE=1 export GALLIUM_DRIVER=llvmpipe export MESA_NO_ERROR=1 dbus-run-session -- lomiri "

Xephyr :5 -screen 1280x720 -extension MIT-SHM & sudo schroot -c trixie-amd64-sbuild -u root --directory=/root -- bash -c " mkdir -p /tmp/runtime-root && chmod 700 /tmp/runtime-root export DISPLAY=:5 export XDG_RUNTIME_DIR=/tmp/runtime-root export LIBGL_ALWAYS_SOFTWARE=1 export GALLIUM_DRIVER=llvmpipe export MESA_NO_ERROR=1 dbus-run-session -- bash -c ' /usr/lib/ayatana-indicators/ayatana-indicator-session & /usr/lib/ayatana-indicators/ayatana-indicator-datetime & /usr/lib/ayatana-indicators/ayatana-indicator-sound & sleep 1 lomiri --mode=shell ' "