Need an email app for ios with huge fonts

since the ongoing problems with dynamic type in the native IOS10 email app, those of us needing very large fonts, due to visual disabilities or circumstances, desperately need a replacement. For those like me needing very large fonts, the IOS accessibility 'pinch' to zoom system is no realistic workaround, as far too much sideways scrolling is needed.
In my case I need an app which can reasonably work with MS Exchange and with Gmail. Essential is that all messages, whether plain-text or HTML-encoded, can be displayed with some kind of a dynamic fontsize definition, with properly wrapped text.
Who has suggestions?