QGIS graphical modeler create files with expression

Question

pros! I am trying to split a point-layer that is stored in an sqlite-database twice using split vector layer-algorithm.

My plan is to split an input-layer by AttriuteA, store the output-files (shp-files, since I didn't manage to write the created layers directly to the database), use theese files to split all of them by AttributeB and store the files in subfolders with the names of the input-files.

This all works more or less with batch-processing but I need to achieve this using the graphical modeler, since I have to try multiple orders of the vector-layer-splitting;

In graphical modeler, no matter if I try to give the expression I use in batch processing to the precalculated value-field in the split vector layer-window or use the Expression Input, it won't work and graphical modeler seems to interprete the Expression as hard-coded (thus creating a folder directly in my home directory).

I have tried using single and double apostrophes. As I'm running out of ideas, I hope someone can help me out...

Below you find a screenshot of my model and the input-field for my folder-creating expression which works in batch processing. enter image description here

Thank you in advance!

QGIS-Version: 3.24.1