Hi indixon,
Welcome to Affinity Forums :)
Are you opening RAW files from a Canon 80D? If so you can already open Canon 80D files correctly in Affinity Photo if you change the RAW Engine to Apple (Core Image RAW). You must have Digital Camera RAW Compatibility Update 6.20 installed to take advantage of it. Serif Labs RAW engine doesn't support the Canon 80D yet.
If you are using RAW's from other cameras check the supported cameras list.
To change the engine used in Affinity Photo open a image, change to Develop Persona, go to menu View ▸ Assistant Manager... and change the RAW Engine (first dropdown) to Apple (Core Image RAW). You can then open the RAW images from Canon 80D.
If for some reason you still want to reset Affinity to its defaults, press and hold ⌃(ctrl) when launching the program, tick all boxes from the dialog that will appear then press Clear.
