Moving to a separate thread as your problem has nothing to do with the (entirely different) WeTek Hub issue.
Amlogic boards always boot from eMMC if signed Amlogic boot code is present in the right sector on eMMC, and you have flashed a ROM image with incompatible (has the wrong RAM chip timing details) u-boot to eMMC so the board is stuck in a boot loop.
The best option is (re)flashing the original Android ROM to eMMC using Amlogic Burning Tool to restore the correct u-boot. The less simple option is manually shorting pins on the eMMC flash chip to temporarily disable the chip so it is not seen and the board will then attempt to boot from SD/USB media. It's not difficult to short the pins, but the problem will be finding a signed u-boot version that supports the board (as they need to support the right RAM timing data) and supports booting from SD card (as the compatible u-boot in an Android ROM will be for eMMC boot and on GXBB/S905 that means the AML signature in the wrong location).
I do not have a collection of old Android boot ROMs (aside from WeTek Play2/Hub) and the only GXBB boards LE provides bootable SD card images for are WeTek Play2 (and Hub, but that has issues), Odroid C2 (which will not boot on anything else due to internal hardware checks), and the NanoPi-K2. So our options are limited and I have low time/interest in changing that.
Searching for old S905 MXQ Android ROMs is the right direction. Flash them and see if they at least boot to a kernel. If they do you can force recovery boot to run Linux again. If they don't, you didn't make anything worse than it already is.