Nature's Call Regalia +X to Summon Briarthorn

[Maya]

And further note, I am by no means even decent at pet builds - this is just something I threw together after gathering some nice greens on other chars and thought “hey physical pet builds suck they say, let’s see what that means compared to other kind of builds” xD

Something I need to point out. Your choice of greens actually fixed part of the problem.
65% total damage modifier on a Pet build with already 1.5k Pet attack on top of all the RR + armor shred = those 15 Phys dmg sources actually do something rather than get canceled out by enemy armor.

Also, the CDR on Briarthorn is a tremendous boost against Cally.

So now that you did show the build, I can safely say that I believe those numbers. Could be faster with GDStashed affixes for perfect rolls and such even.