Kernel-core error at install

I try to build a small rocky linux image (8GB) with the minimal-install & ANSSI-enhanced security profile applied. I use the dvd install.
The profile asks for a peculiar partitioning scheme and each one of my tries ends with a :
dnf error error in POSTTRANS scriptlet in rpm package kernel-core

I think it’s related to how I size the partitions because a minimal install with automatic partitioning works fine (but I can’t apply the profile).

Here’s my last attempt :

/boot            >> 512MB
/opt             >> 16MB (not used)
/tmp             >> 128MB
/srv             >> 16MB (not used)
/home            >> 128MB
/usr             >> 2GB
/var             >> 512MB
/var/log         >> 1GB
/var/tmp/        >> 128MB
/var/log/audit/  >> 128MB
swap             >> 2GB
/                >> remaining space

Do you have an idea what’s wrong here ?

actually, when I build a 20GB image, giving at least 1GB to each partition, everything works fine.
I’ll start from there, reduce each one progressively and see where it leads.