Without this basic function how would you insert math equations that flow with the text, for math teachers like me? Even MS-Word does that, isn't it? Don''t tell me that this 2018 software is not going to support math! If it is so, then it is just Affinity Designer Plus, not a desktop publishing program for science teachers or students.
I am still using Corel Ventura 10 - one of the best desktop publishing programs of those days. Even now it serves most of my high school level math publishing requirements. I have to run the software in XP comptibility mode under Win 7 and it works. I thought I should come out of that at least now.
Corel stopped its development in 2002 and it has an intermediate level (if not advanced level) equation editor built-in right from its first version and can be used straight out-of-the-box! Still wonder why most of the DTP packages give a step motherly treatment to put in Math equations in documents. A sample page from the legacy software Corel Ventura 10 attached.