So, you wanted to know how to build an AppleTalk Raspberry Pi bridge to the Internet? Here it is, I found the information when searching for a different topic. Also, I’ve found a URL to the Inside AppleTalk documentation and some other useful AppleTalk information.
20191026/https://68kmla.org/forums/index.php?/topic/58137-appletalk-net-cable/&tab=comments#comment-621400
20191026/http://www.applefool.com/se30/
20191026/https://www.macip.net/macippi/
20191026/http://www.tmetz.net/os/Apple/Inside_AppleTalk.pdf
In the old days, people had to use an expensive Shiva FastPath router box if they wanted to connect a Macintosh to the TCP/IP Internet proper.
20191026/https://en.wikipedia.org/wiki/FastPath