There are expensive ones that do a really good job of blocking light, and inexpensive ones that let some light through.
Walmart's house brand, Mainstays, is the later. They block a decent amount of light, but some will get through.
I found that if you use blackout curtains with grommets, like the Mainstays [1], you can simply double them up. Set one panel on top of another with their grommets aligned, and you have a double blackout curtain. A pair of $10 Mainstay panels doubled work as well as the expensive ones which are way more than 2x$10 per panel.
If you need more than one panel (or pairs of doubled panels) side by side to cover your window, the grommets can help there too. Overlap them side by side by a couple grommets. You've now got effectively one wider panel.
[1] https://www.walmart.com/ip/Mainstays-Blackout-Energy-Efficie...
When watching TV the bright reflections in the screen from that window can be quite annoying, especially during darker scenes. During parts of some days you can actually see a reflection of the sun itself in the TV screen, making it hard to see even bright scenes.
Without that, there would be absolutely no reason to even think about a technological solution for waking up with the sun.