dtech see if you can backport systemd/busybox: allow configuration of persistent logs and journal by mglae · Pull Request #5537 · LibreELEC/LibreELEC.tv · GitHub and then use /storage/.cache/journald.conf.d/00_settings.conf with something like:
[Journal]
SystemMaxUse=10M
MaxRetentionSec=0
RateLimitInterval=0
RateLimitBurst=0
The settings add-on changes are in Add persistent logs and journal configuration by mglae · Pull Request #233 · LibreELEC/service.libreelec.settings · GitHub but we rewrote/restructured most of the settings add-on since 9.2 so those won't backport.