Multiple photos/videos exist of downed YIHA/Asusguard models (including a pretty famous one of locals in Pakistan beating up the wreckage of a YIHA, thinking it's an Indian drone) so saying that not a single one was shot down is objectively not true.
The presentation lists how many locations were targeted, but doesn't say anything about how successful those strikes were. So "successfully struck military targets" is a leap of an assumption. IIRC, that presentation also had a slide which said something like ~90% of airborne attacks with drones/long range vectors were thwarted/intercepted.
What we do know is that Indian AD must have recorded airborne signatures matching TB2/Akinci - which is how they know they were 'used'. But what that use entailed, we do not know. Were they being used in a combat role, or were they doing ISR/BDA/comms relay while the kamikaze drones like YIHA went in?
That we do not know.