Without any postprocessing AA, you’ll have to rely on texture filtering and render resolution to mitigate aliasing. You could try blurring the mipmaps of the emissive texture by choosing one of the blur filters in the mip generation settings. Making sure anisotropic texture filtering is enabled for the texture might also help.
If the issue with text is with UI widgets, it is likely because the built-in class does not have mipmaps enabled. To enable them, you would need to make a custom class in C++: