Good point. However fonts can be installed/shared into apps is fine by me. Fontasy is just one option I saw that allows import specifically into LumaFusion. I discovered also that ProCreate is one on the share list.
Now, to answer my own question, I just found a workaround for Affinity: I can use Fontasy to add fonts to a folder on my iCloud account by adding to the Folder app. Then within an Affinity iPad app, I go to Preferences/Fonts and select the Cloud icon and select the font in that folder. What’s cool is once you do this in one Affinity app (say Designer) it automatically adds those fonts to Affinity Photo. So you can use any means to get fonts into a Cloud folder, then import them into Affinity. So essentially, problem solved. ;~)