Not trying to be a buzzkill but I'd be cautious with stuff like EMF protection stickers. A lot of them don't have solid scientific backing and some have even been tested and found to do literally nothing.
I get that migraines are brutal (I've had my share), and I totally understand wanting to try anything that might help. But these kinds of products often play on fear or uncertainty around "radiation" even though everyday EMF levels from phones/laptops are super low and already regulated.
If it gives you peace of mind, cool. But personally, I'd put my money toward things with more proven results.