iOS14's App Tracking Transparency changes reduced how much conversion data platforms like Meta can see directly from devices, which typically causes under-reported conversions, delayed data, and modeled rather than observed results in-platform. The practical fix most GCC advertisers reach for is server-side tracking through each platform's conversions API, sending events directly from your server rather than relying solely on the browser pixel.
Server-side setups are not a full fix — they improve signal quality and timeliness but don't recreate pre-iOS14 precision. Treat in-platform numbers as directionally useful once CAPI is in place, and lean on CRM or revenue data as the source of truth for real profitability decisions.