If u want to try your luck, Cougar 200K should be very similar to Logitech K740 (flat KB with scissor switches) but it's cheaper, around $30. I have no idea how good it is in practice but at least it doesn't have keylock on space+arrow keys. Another similar KB with scissor switches is Cherry Stream 3.0 but I read it has keylock on space+arrows so u would need to remap space.
Considering u are using a laptop kb atm, u should be at home with K740 or similar!