Many of the support benefits contain the condition
"Until the start of your next turn, your Strikes that deal damage to a creature that your companion threatens"
Strikes are defined as (pg 471)
"You attack with a weapon you're wielding or with an unarmed attack"
implying that only weapon or unarmed attacks count as a Strike, but not spells. Neither the "Cast a Spell" action nor the "Spell Attacks" section indicates that a spell is a Strike, and the Attack tag explains that it could be "a Strike or ... another attack action."
All this leads me to believe that the cantrips available do not count as Strikes for triggering the support benefits of an animal companion. I just want confirmation, or someone to point me to something I may have missed, since this significantly reduces the utility of animal companions for druids, since weapon use is not a strong suit of theirs.
I'm not interested in builds that make this viable (well, I am if it's awesome, but that isn't the purpose of this question) - I am aware of Order Explorer (Wild) and/or Shillelagh making it somewhat viable.