cant you use wire to bridge over the missing pcb track?
Im not rly good with soldering but i can recommend watching “Louis Rossmann” on youtube, he had similar problems and fixed easily(well he is kinda a genius at that tho 😛 )
Otherwise you will need to watch ebay for broking cubes, i dont think getting replacement parts is ez or more likely immposible…, especially since the motherboard is the main part of the tablet(cpu,gpu all the shit what it makes a tablet).
Try to contact cube directly i guess.
Gl bro