Honestly, finding a slim, backlit board that doesnt feel like a toy for under 75 bucks is a nightmare... most are unfortunately pretty flimsy and disappointing. Quick question tho, are you typing on your lap or those tiny train tray tables? If you have a table, the Seenda Backlit Bluetooth Keyboard Multi-Device Slim is way under budget, tho the build quality feels a bit cheap.

Finding the perfect one is a struggle, unfortunately. I had issues with the Keys-To-Go as well, it felt mushy and was not as good as expected for the price... super disappointing. These are way more solid for train rides:

• Arteck HB030B Universal Slim Portable Wireless Bluetooth Backlit Keyboard
• Satechi Slim X1 Bluetooth Backlit Keyboard The Satechi is sleek and hits your budget perfectly. It actually feels like a real keyboard.

Quick reply while I have a sec. Tbh finding one that feels good for typing but works with both screens is a challenge. Not sure but I think I heard about some ultra-slim mechanical boards that might fit your budget. I have been super satisfied with using a generic compact keyboard and a separate stand lately... way more stable on the train table than those flimsy folding covers usually are. Those thinner ones usually have better travel, IIRC.