Scan at high resolution 600+ PPI.
Load into Photopea.
Crop.
Make Black and white layer
Adjust so layers you want are black
Add Threshold Layer
Add regular layer, paint out speckles as needed to clean up design
Group all layers
Double click group, set blend if > Current Layer > move Right Carat slightly to the left. This make the white transparent.
Select Image Layer (Likely called "Background") add filter > blur to taste to smooth out small faults.
Export at PNG
Load image into VTracer.
Set to "Color", "Stacked"
Adjust Parameters to get a clean vector
Export as SVG