How do you create memorable poster for top tier conferences ( ICML/ICLR/NEURips ect…) [D]

Hello everyone,
Presenting at a top-tier conference for the first time and having a very hard time coming up with an appropriate design for my poster.
Everything I do seems basic and banal. My paper is more theory-oriented, and apart from putting math formulas in bold in the middle, I am not sure what the best way is to design the poster. Even the sizing choice is complicated as ICML gives 3 different recommendations to pick from, and somehow from my computer, I can’t see how the PowerPoint slide will look like printed on those dimensions.
And
Printing a poster is nearly $100 CAD, so there’s no room for trial and error.

So
If anyone has any tips on how to do it properly,
I have been using PowerPoint, but perhaps I should go to Canvas? Or
Does anyone have another software to recommend?