Does a router need ARP to send data to router in anther netwrk, it already has the IP address of the interface right?why does it need the MAC address? [duplicate]

Question

i am studying off this

https://www.practicalnetworking.net/series/packet-traveling/key-players/#arp

but my question is if ip address is for end to end communication , how is the end to end happening when all it is just hop to hop using MAC address?i understand they gotta encapsulate the L2 header with a MAC but please forgive me if i am wrong but it seems like IP addresses's use in network communication is to get the MAC address.I am not talking about in LAN network communication,i understand mac is important there , talking about network to network.Is ip address just a bunch of hop to hop mac communication?