I have virtually zero knowledge of The Odyssey as a Greek mythology, save for a few recognisable names like the Helen of Troy, the Trojan War etc. I do want to enjoy the movie to its fullest, and if learning about the plot material is essential to it, then so be it. Is there a good resource giving a summarized version of the plot enough to understand the film? If so, I would really appreciate it if you shared it here.
I haven't watched it but I'd say to try what was my approach with The Lord of the Rings. Watch the movie. If you liked it or if you felt the need to know more about the story, read the books and every other related thing. Then watch the movie again.
You have only one chance of watching the movie without previous knowledge.