Ran through each dtb using the latest CoreELEC-Amlogic-ng.arm-9.2-nightly_20200218-Generic.img build on the Droix X3 and here are the results using both the internal NIC and an external USB NIC.
Not working - Permanent black screen on the TV.
g12a_s905x2_2g_1gbit.dtb
g12a_s905x2_4g_1gbit.dtb
sm1_s905d3_khadas_vim3l.dtb
sm1_s905x3_2g_1gbit.dtb
sm1_s905x3_4g_1gbit.dtb
Not working - Continual Reboots.
g12b_a311d_khadas_vim3.dtb
g12b_s922x_odroid_n2.dtb
g12b_s922x_odroid_n2_dvb.dtb
g12b_s922x_ugoos_am6.dtb
g12b_s922x_ugoos_am6_rev_a.dtb
Not working - Continual Reboots & Corrupt boot Logo.
g12b_s922x_beelink_gt_king.dtb
g12b_s922x_beelink_gt_king_rev_a.dtb
CoreELEC Working but with no detected network or bluetooth devices (internal or external)
(Note: Both g12a device trees boot the initial partition formating screen and once complete require a hardware reboot before loading CoreELEC. The sm1 device trees do not require this extra step.)
g12a_s905x2_2g.dtb
g12a_s905x2_4g.dtb
sm1_s905x3_2g.dtb
sm1_s905x3_4g.dtb