Looks like there might be a bug. Sometimes it works, and sometimes it doesn’t.
Memmy - An iOS client for Lemmy
Didn't work for me, on ipad at least.
It worked for me when I viewed your post in my iPhone, then when I navigated away from your post and came back, it stopped working.
I tried on my iPhone and got no joy. The only big text is when I’m replying to your message. My own text is large, so they haven’t broken that yet.
As a workaround, on iOS you can choose per-app accessibility settings among which there’s font size. Does that not work?
I think Android should have something similar but I’m not sure.
I used that workaround on other apps that don't support dark mode. Did not work here for font size. The devs actually have to support it, which they are actively steering away from on each new build.
Like I said, the font size should have actually increased now, not decreased. Can you let me know what device you are using and show me a screenshot? Not saying you're wrong, and if this is the case I definitely want to address it.