I'm attaching a patch that fixes the jagged text in the source SVG and adds a variant of the poster. And here are PNGs from each of them:
Original (fixed text):
https://luis-felipe.gitlab.io/media/2022/01/Guix-Days-online-2022.png
Variant:
https://luis-felipe.gitlab.io/media/2022/01/Guix-Days-2022-Variant.png