My current workflow (using illustrator and the Astute Graphics Inkscribe tool) is to eyedropper a colour, Draw a closed shape, deselect, then eyedropper again, then draw a second shape off the points/nodes of the previous.
I cannot replicate this in Designer (or Photo) with the pen tool. Playing with the snap parameters allow me to, to an extent, draw off the first shapes points but there's no way to give snapping prominence over the general sides of said shape so accuracy cannot be maintained.
I understand this is probably quite a difficult thing to explain, but the Affinity tools seem halfway there so would be amazing if I could switch 100%.
Failing that please encourage Astute Graphics to enable their Illustrator plugins to work in Designer!