Thank you. I know I am desperated.
I started from scratch again. Following all instructions of Simple debricking method, as well as the small debricking guide for noobs.
Since my fastboot is working, I start again by flashing the 3 imgs into the KT.
1. mmcblk0p2_ssk.img from "Small debricking guide for noobs"
2. kt_5.0.0-diags_kernel.img from pastebin
3. kernel-5.0.0.img from pastebin
And after setvar bootmode diags and reboot, it loop on the tree again. No sign of the diags menu.
Thus, no SSH and further steps for me to follow in those guides. If the problem is what suggested, how can I fix it under the current status?