I had a very pleasant surprise this morning when I saw this review of KeyPad on softpedia.
https://mac.softpedia.com/get/Word-Processing/KeyPad.shtml
Does the job, and it’s free
There are other apps that offer similar functionality, but the ones I’ve come across tend to be paid. KeyPad is completely free, and it worked perfectly with my iPhone and iPad. Some other features might be nice, such as an option to customize the global hotkey or hide the app from the menu bar, but they aren’t essential by any means.
Made my day! Thank you Catalin Chelariu!