Creating graphics on iPad workflow advice

Hi all,
I’m looking for advice for creating custom graphics for import into Dorico. On occasions where I am recreating a handwritten score that has unique lines or drawings I have done this over the years using a Wacom tablet and drawing them into a vector graphics program.
I would love to keep the general workflow but use my iPad Pro with the Apple pencil to draw since it is much more accurate than the Wacom. So I would need to import a pdf of the page of notation in question, draw freely in a new layer and export that layer accurately as svg.
Can anyone give me some advice about apps that would be best suited for this and/or any other workflow tips? I don’t really want to try out a slew of paid apps to find they are not suitable. Affinity Designer for the iPad didn’t seem to do it, though I don’t remember specifically at the moment what the problem was.

Thanks in advance!