It took me a while to figure out a functional way to convert my existing line work from Photoshop's Vector paths to designer but here's the work around that I found after some experimentation. I've also included how to do the reverse just in case someone needs to go back and forth.
Live Stream Video Tutorial Link: https://youtu.be/b_2ajSD4uFM
Line Work conversion Select 1 vector mask layer at a time + File + Export + Paths to Illustrator+ save as individual files
File + Open in Illustrator + check the following ( Legacy Art board + Crop Area(s))
Organize paths into separate layers + stroke paths so you can see them
Save as Single EPS document
Open file in Affinity Designer
Click the Group Thumbnail + Add Stroke Color + Line Thickness + select following according to your preferences (Cap + Join + Align)
Bringing Files into IllustratorDisable all clipping masks - clipping masks will cause the layer to be rasterized
Export to SVG format to maintain proper grouping
File+"Place" the image in an Illustrator file that's the same size
You'll get a brief error but if you ignore it a dialogue will appear (simply click ok)