I really would like to customize my header styles (other styles). H2 on VS Code and Github is not italicized and triggers my OCD on Agenda (to the point where I don’t use it). But Markdown lint complains about missing H2 or using H1 multiple times.
Any thoughts on this (I fully admit it feels like a me thing).
Thanks!
We would certainly like to give more control over styling in future. Not sure yet exactly what form it would take (eg customize every style or theme sets), but it has been on the roadmap for a long time. Other projects keep getting in the way 
I agree. The Italic H2 and H4 headings do not look very good.
A good comparison could be Bear Notes (beta v2) that allows any font to be chosen for the headings and body text, as well a separate font for the fixed-width.
I think Agenda needs to implement 3 options at least.
The number of font choices may still remain restricted to the current ones (or maybe a few more)… but the choice of style (bold, italic,etc…) and size is a must.
Again we want to stay away from turning Agenda into a Word processor, but we can see how in the future you could configure themes perhaps and in that way give more control.
I think the ability to just choose fonts (and maybe relative sizes) does not tread towards a full word processor… 
Bear Notes does provide a limited set of font editing features… and it is not becoming a word processor either.
I agree that Agenda should NOT become a full fledged word processor… but I do think it can gain a few more bits than it has today !