You can find the Affinity Photo donut tool ? In the toolbar below the rectangle.
Hole radius, start angle, end angle, total, invert and close.
You can create a thick radius (less than 50%) for a hollow circle / ellipse or you can set it 90% and above to create a very thin loop. This can be done via the control bar or via the interactive dot on the generated shape.
You can change the pie setting start and end. Create a small arc using 12 / 45. Create a semi circle / arch by entering 0 / 180.
You can also filled the design with gradients or patterns / bitmaps etc as well as fill it with other shapes by using the paste inside command. Create a circle and cut it and then selected the generate ring design and use the edit menu and paste inside. You can then duplicate that artwork multiple times to fill the artwork with the different designs,.
You can also duplicate the artwork by holding down the alt / option key and dragging. You can then fill the entire image with this design, you can use the fill to change the color of the artwork across the document. You can then merge visible to merge them all into one pixel layer.
You can also use the right click option and select convert to curves and then manipulate the curve by using the node tool. You can manipulate the artwork to create many variants of the overall theme with minor tweaks to the points.
You can select it and apply it and create any size of design, it is a vector. You can also distort it and modify it in countless ways using the interactive settings. You can also apply effects to it via the fx button at the bottom of the layers panel. You can also go to the layer menu and rasterize it (and deselect the fx if you have added some effects) and then go to the layer menu and create new pattern layer using selection. You can then manipulate the design in countless ways. scale and rotate and shear and more as well as duplicate it and apply with blending modes and more.