Migrating/Transferring old to new MacBook Pros

I am having issues migrating/importing between my mid-2012 MBP 15" & my new 2019 MBP 16". My old MBP has a 500GB HD that is mostly full (450GB). My new 2019 16" has a 2TB drive. I have owned Macs since the 80's so its probably best to transfer vs migrate this time but I'm not sure what are inherent issues and what specific to my machines ... and most importantly what is the FASTEST / EASIEST route to transfer info.

My new 16" sees my 15" in my wifi network but the file folders are empty 0kb. 16"MBP is erratic in identifying/accessing any of my backup USB-3.0 SSD drives and won't transfer (plugged in via a Totu 2-port USB-C hub). I can migrate from TimeCapsule on wifi but that's brutally slow. And finally my mid-2012 MBP doesn't see my 16" MBP at all on the network.

Hoping someone can hep, and let me know if my problems are an issue with my particular devices, with the new machines/OS, with going btwn USB-3.0 & USB-C, &/or how best to get this mega transfer done.

Mid-2012 15" MBP = 2.6 GHz Quad-Core Core i7 / 16mb/500GB

2016 16" MBP = 2.3 GHz 8-Core i9 / 32GB/2TB

All running Catalina OS 10.15.1

BTW - I've just ordered a new USB-C 4TB SSD • USB-C/USB-3.0 256GB Flash Drive • USB-C cable for my old portable backup drives. That should all arrive in a few days. I figure something in there's gotta help!

Thanks for your insights & advice!!!

Glen