If you work with ClickBank, Digistore24, or BuyGoods offers, you will find a perfect match with RedTrack.
Start with native ClickBank INS integration. Add built-in API cost updates for Facebook, TikTok, Taboola, and other popular ad networks. Add CAPI support and built-in Automated Rules and Ads Manager. Result — ad tracking solution of choice for media-buyers and vendors driving traffic to ClickBank.
You now know RedTrack has accurate data, API cost updates and CAPI support. Maybe automaton rules or ads manager. Digistore supports S2S conversion tracking and does not require special integrations etc.
With BuyGoods being 3rd on the list we have an answer to the questions you want to ask. No, there is still not S2S postback for initiate checkout, but we can help you with custom tracking scripts to obtain almost S2S level of accuracy.