One approach you could take could be to compute this score outside of Braze (e.g. in your data warehouse) and then feed it back into Braze as a user attribute or via Segment Extensions.
As Ted mentioned, unique clicks are typically the strongest engagement signal (excluding things like unsub, app download links, etc). If you have access to data points such as unique_opens_real and/or email_clicks along with their timestamps, you could possibly use those data points to build a more dynamic scoring model.
For example, you could implement a time-decay model such as:
Email Decay = User Action × Decay Factor ^ Days Since Action
Where you might define User Actions as click being worth 5 points, opens worth 2 points and a decay factor of like 0.8 (depending on how aggressive you want engagement to decay)
Then you could sync the resulting score (or even a tier like High/Medium/Low) back into Braze for segmentation and targeting through a Custom Attribute on whatever cadence you like.
That's just a thought of mine but definitely keen to hear how others are approaching this. And +1 to Ted’s point - definitely test and validate before rolling out!!
