New to the group because I just got my first AR and curious if there are tactical scenario competitions that cater to the AR platform that do not require multi-gun.  I am not interested in investing in a pistol and shotgun due to cost.  Not finding anything when I searched here and on Google, other than some defunct organizations. Thanks

If you haven't searched Practiscore, I would start there.
I think you will be hard pressed to find rifle only comps or comps where tactics is a priority.
2 gun is getting more common where the AR dominates, and you use a pistol.
PCSL is becoming popular, but it isn't based on using any tactics and is purely an "action" type event.
Maybe search for "Minuteman" events. They seem to be rifle focused with tactics as a priority, but there are few of them around and normally held by local clubs without alot of advertising. I still don't think you will get away from needing a pistol.

Practiscore
PCSL
Minuteman