I had good results with the Amazon Basics CR2s - I last bought two 12-packs in April 2020 for an effective $1.49 per battery. All of those are in Iris v2 sensors at this point, some up to 20 months. The oldest report 78% or 87% remaining. The 12 pack is out of stock at this point, however.
I've since moved onto using EBL rechargeable RCR2. I'm really happy with these and highly recommend them.
(I have about 100 sensors using CR2s)
