How to increase font size in apps on iPad 13?

I just got a new iPad 13. Certain apps I use often, like Lumo and Duck Duck Go browser search results, have unreadably small text font. I have adjusted font size in general and accessibility settings, but it only affects headers and icons, not the actual text in regular apps that I need to read.

The screen also doesn’t move if I pinch to zoom it larger.

The header bar with the date at the top of the iPad screen is also unreadably tiny. Pretty sure it’s a pt. 8 font, much like Lumo’s AI responses appear to be.

[Re-Titled by Moderator]