Use the Affinity Photo brushes with symmetry, as the brushes can be rings or any other design, literally zillions of artworks can be created using this powerful technique
It doesn't need to be a ring but for the purpose of this tutorial, that is the design used. It can be created very quickly using the donut tool and set the hole radius to be 70% (set that in the control bar). You can also fill it with anything, such as a gradient using the gradient tool and you can also add styles effects to it via the fx menu command (right click donut shape) and go to the bevel and set the radius to 20px etc and go with a type of pillow. Go to the layer menu and rasterize and deselect the fx option and then go to the brushes panel and right side command create from selection. Remove the design.
Edit it by double clicking the entry in the panel. You can then set the spacing really low so the dabs are applied rapidly so it looks like a flowing nozzle design, go to the dynamics section and set the size jitter to pressure. Set the size low, perhaps 200 or so as it may get very slow if you try and apply a 2000 px sized design to the mirror.
Select the paint tool and then goto the control bar and set the symmetry to ON and set it to 8 and set the mirror to ON and set the lock to ON to avoid moving the center by accident.
You can then apply it using an art pad / pen (though a mouse is fine) and generate your initial design. Weave it back and forth to create a wavy design that is duplicated around the entire image.
Go and apply a filter to the current background design such as Gaussian blur or another such as box blur etc Youtube video on subject
Create a new via the layer menu
This time apply the stroke but avoid going over the edge or outside of the document. You will end up with a sharp dividing line if you do that as the stroke does not extend beyond the document. Create a subtle small design
Right click the design and select the layer effects command and add a 3D effect such as adding profiles, type, depth etc Youtube video on subject
Hold down the alt / option key and duplicate this entry and apply across the entire design.