You don't have to jailbreak your Kindle, or render images.
You can just point its web browser at any webpage you design, and disable the Kindle's "screensaver" (its ads or sleep screen) with debug commands [1, 2].
You'll be stuck with a browser bar along some edge of the Kindle (you can rotate the device orientation to put it at the bottom or right edge), but it's a small price to pay for being able to write your weather/transit/news screen in easy HTML/CSS/JS and whatever backend language you want, and run it on a cheap DigitalOcean $4 instance or whatever.
You can just point its web browser at any webpage you design, and disable the Kindle's "screensaver" (its ads or sleep screen) with debug commands [1, 2].
You'll be stuck with a browser bar along some edge of the Kindle (you can rotate the device orientation to put it at the bottom or right edge), but it's a small price to pay for being able to write your weather/transit/news screen in easy HTML/CSS/JS and whatever backend language you want, and run it on a cheap DigitalOcean $4 instance or whatever.
[1] https://blog.notfaqs.com/2018/06/kindle-e-reader-disable-scr...
[2] https://www.mobileread.com/forums/showthread.php?t=198334