What is the difference between bridge mode and DMZ?

Question

Computer networks

2 routers are connected in series. The task is for the second one to have a white IP address, and the server behind it to be opened from the Internet. To do this, you need to do port forwarding on the 2nd router. The first router must be switched to bridge mode, or you can set the DMZ Host. What are the differences between these modes of operation?