u/Any-Battle1038

Hi everyone, I need some expert advice on optimizing Meta Ads for a WApp-heavy funnel (women's apparel).
The Problem:
About 70-80% of our sales are closed manually via Instagram and Wp, then manually entered into our e-commerce backend. Because the Meta Pixel only sees direct website purchases, our in-platform ROAS looks like 0.5, while our true ROAS is actually ~10.
Because of this, Meta is optimizing for "message senders" (people just asking for prices) rather than actual "buyers", and our lead quality is dropping.
My Questions:
I want to feed this purchase data back to Meta to train the algorithm.

1. Offline Event Sets: If I manually upload a weekly CSV of Whats APP buyers (names/phone numbers) as an Offline Event Set, will it actually improve ad optimization? (An industry vet with 15 years of experience told me offline conversions are useless, so I'm a bit conflicted).
2. CAPI for Manual Orders: We have Conversions API (CAPI) active on our store. Since we enter these Whats app orders manually via our admin panel using our office IP, is there a way to pass this purchase data to Meta via server-side cleanly, without messing up IP matching or deduplication?
3. What is your go-to strategy for training the pixel in D M Whats app heavy e-commerce business?
   Any insights would be hugely appreciated. Thanks!