The -3 full ROM is available. https://forum.xda-developers.com/moto-e5/development/rom-stock-android-8-0-0-rom-moto-e5-t3806530
And don't beat yourself up. With these newer Moto smartphones, and Android Oreo source code in general, a great many things have changed.
I meant the 1921-3 variant stock rom for tmobile not the -3 build lol