Workflow described here in the meantime:
# Install Kapture
pip install kapture
# Bundler -> Kapture
py C:\Python310\Scripts\kapture_import_bundler.py -v debug -i dataset-bundler\bundle.out -l dataset-bundler\imagelist-local.lst -im dataset-bundler\images --image_transfer link_absolute -o dataset-kapture --add-reconstruction
# Kapture -> Colmap
py C:\Python310\Scripts\kapture_export_colmap.py -v debug -f -i dataset-kapture -db dataset-colmap\colmap.db --reconstruction dataset-colmap\reconstruction-txt
# Colmap txt to bin conversion
mkdir dataset-colmap\sparse\0
COLMAP.bat model_converter --input_path dataset-colmap\reconstruction-txt --output_path dataset-colmap\sparse\0 --output_type BIN