I have just bought a new iMac and have hardly any software on it. I have installed Affinity Designer, Photo and Publisher and opening files is very slow, maybe a minute!
So I created a new web file, which opened very fast, but when trying to close the new empty file it look a long time to close, the wheel of death was spinning for a long time.
One of the reasons I bought a new iMac was to speed up my applications but it has done nothing to speed up the Affinity software.
iMac (Retina 4K, 21.5-inch, 2019)
Processor 3 GHz 6-Core Intel Core i5
Memory 8 GB 2667 MHz DDR4
Graphics Radeon Pro 560X 4 GB