Sharing WiFi to a Copper Ethernet port Linux Mint 19.3 not working

**Environment**
Seeing as Linux Mint uses the same networking stack and manager that Ubuntu does, I felt it most appropriate to receive a response in this forum. Here's my setup: Lenovo Thinkpad with excellent WiFi connection. Macintosh running second latest version (still supported) with shotty WiFi. In the main Gnome Network Manager window I do not have the option to "edit an ethernet profile, switch to IPv4 and then change IP Addresses to Shared". However when I run nm-connection-editor, I can create a profile that does have the option to share from another connection to my gigabit copper ethernet port. **Configuration and Troubleshooting Details**
Following the steps outlined here for Ubuntu 14.04 and 16.04: https://help.ubuntu.com/community/Internet/ConnectionSharing The Network Manager then tells me the IP is set to 10.42.0.1 with no other information. And then manually setting an IP address to the Macintosh with the following settings: IP 10.42.0.2 Subnet 255.255.0.0 (Also tried 255.0.0.0, 255.255.255.0 but the notation of 10.42 suggests a /16 subnet mask). Default Gateway 10.42.0.1 DNS set or unset to a public DNS does not help. The end result is that I cannot ping 10.42.0.1, 1.1.1.1, 8.8.8.8, anything else public or my WiFi LAN devices. So this double-NAT'd sharing is not even letting me ping my Lenovo from the Macintosh. Additionally the Lenovo cannot ping 10.42.0.2. I've tried changing the MTU, Duplexing, Link Speed, etc, but the cable is functional outside of this environment. Thanks in advance for your help.