Debian Trixie on TS-112P

Hello,
I've been using Debian Bookworm on my QNAP TS-112P, which works well after
the repartition due to kernel size.
However, sometime within the testing phase of Trixie the system broke.
The system fails to boot because systemd-journald.service fails with SEGV.
I have full serial console access for debugging and I can also boot from
TFTP by issuing some U-BOOT commands.
I did attach the SSD to another PC and confirmed that the SATA SSD is
hardware-wise and filesystem-wise completely fine
and I was able to update the system to latest stable trixie (at the time of
writing) using qemu-user-binfmt and chroot.

The only way I was able to "debug" in any way or form is to add
"systemd.unit=emergency.target" or "init=/bin/bash" to the kernel bootargs.
However, in emergency mode I can't access ethernet (nor mtdblocks).
How can I debug why journald segfaults, or how I can collect and provide
logs for debugging this issue?

Best,
hoch10