With the help of Pixilart, I created a simple animation with a tennis ball rolling as the transition and then used this Tennis API to fetch the matches of the day.
Here, you can see it running on the emulator, and here, you can see it running on my Tidbyt. The video links will expire in a day, so I may need to upload them somewhere else.
There are still a lot of "TODOs" on the codebase, including some nasty tricks I did to the interface, obfuscating the API keys, etc. The "flag" colors are also not working from the API, so I might also think about something else there. I should have a PR at some point next week :)