Mystery Plant…

I’m trying to figure out what this plant Folia is.

Mystery Plant Leaves and Reddish Branch

It’s a voluteer plant that has serrated leaves and a reddish truck and branches. Some people suggested that it is a Brazilian Pepper Tree (Schinus terebinthifolius), but the leaves don’t quite match the photos I’ve seen.

Click below to see more photos.

Unknown Volunteer
Leaves as a young plant

Repotted Mystery Plant
Whole plant

Mystery Plant Roots
Roots

This is growing in Vallejo, CA, USA (Northern San Francisco Bay Area), Zone 9a.

Anyone know what this plant is?