But DTB, I can't understand, so I can't solve it by myself. I hope you can help me adapt it!
Okay, I found something that will hopefully be useful.
The Tronsmart Vega S89 device (it doesn't matter if it's Elite or Standard) is based on a Meson8 reference board type "k200" layout.
First, use this image to create the SD card:
I found two devices with the same type, you should try this first:
The downloaded file must be renamed to "dtb.img" and the existing one must be overwritten on the SD card.
Then try booting from SD card and check Ethernet connection.
If Ethernet still doesn't work with the first dtb file, you need to try this one: