I figured out the image with a show command and just changed the xalign and yalign to be in the upper right corner for all achievements, I tried to do the code you replied with and it just keeps getting me exception errors but I think it is okay with just an image sliding in.
Yeah... any customization is possible, but I think screen language is beyond the scope of this topic
I'd join the official Ren'Py discord and see if you can get some general pointers on screen language (or just google some tutorials)... the achievements screen is just a standard Ren'Py menu screen (similar to the Preferences or About screens) so you can customize it in any way you can customize those screens