There is more than enough lore for a MASS EFFECT series without diving into Shepard's arc.
First thought is the FIRST CONTACT WAR or Anderson's adventures.
Alternately, the Batarian Wars or conflicts with the Geth between First Contact and Shepard's time.
Young Anderson would be a good protagonist choice and it would explain why he was later Earth's first Spectre candidate. So the show could explain what how kickass an N7 is, even if not a Spectre.
Main thing is don't let any of the Veilguard writers anywhere near the writer's room; do involve Casey Hudson and/or Drew Karpyshyn. And do let the FALLOUT show the way: a separate story in the same milieu, independent of the games, much like the novels.
It is a fine IP to mine. Hopefully they won't mess it up.
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