TP link WPA8631P v4 bricked trying to install 23.05.4 release

Hi community

After successfully flashing 23.05.3 on two WPA8631 devices, I figured I'd upgrade to the latest version. I have some issues with random reboots, in as far as I can tell a OOM error.
I tried to sysupgrade to 23.05.4 from openwrt 23.05.3 with the latest stable sysupgrade version.
Apparently all seemed to go well yet the unit is unaccessible, I can only use failsafe to get into the unit, firstboot doesn't work...

So I loaded the same, newly downloaded version via SCP, after sysupgrade I got into bootloop.....

So that didn't go to well..

I ordered a replacement unit so OEM version, tried flashing factory openwrt 23.05.4, same thing, only failsafe mode possible.

So now I have 2 units not working....

I guess it's time to ask for help on how to proceed.

Unit 1 : in bootloop

I already opened it up and have a working serial connection, uboot seems intact
I have a Screendump available
It fails with 'Uncompressing Kernel Image ... LZMA ERROR 1 - must RESET board to recover'

I could use tftp to load a working version ?

Unit 2 : failsafe mode

I can still upload firmware using UTP, unsure on how to proceed, which version ?

So yeah I'd be glad to get some help with this please
Diego