Check my 2nd post here in this thread, worked for me: https://techtablets.com/forum/topic/hi10-air-bricked-after-changing-bios-settings-how-to-reset/#post-181382

Did you try the BIOS reset procedure with a keyboard in my 2nd post?

I was holding escape while trying to power it on, kinda surprised it worked. Only settings I messed with were Ram frequency and vram size. It reset both settings when it did finally come back to life again.

I did the same thing changing ram frequently.
Plug in a USB keyboard, hold power for 13 seconds if not more. Make sure its charged. Then power it one pressing esc on the keyboard, it should reset the bios to defaults. This unbricked mine.

Only setting you should mess with is vram size, 256mb max.