since pets scale with neither the player’s +% damage or OA, is it best to dump all points in physique for a pet heavy build?
Your intuition is quite good. Physique is usually the best choice for stat points on an overall basis, especially for summoners.
There is a key caveat, though. You’ll want to plan out your end game gear so you know in advance what stat requirements you’ll need to reach in order to wear your desired endgame gear. For example, you might need higher spirit requirements to wear some endgame jewelry, or perhaps some other item.
If you don’t know what your endgame gear will look like, then it might be best to reserve your last 20 stat points, or thereabouts, to see where you might need to allocate them after your endgame gear picture starts to clear up.
For reference, the conjurer summoner build is around 720 spirit