How much are the numbers off what you are seeing? The numbers will always be inaccurate because Meta cannot track everyone post iOS14. We've had clients try Hyros but even those numbers did not line up perfectly. You can look into implementing the conversion API with Meta. Simplest and lowest cost method is to just keep a google spreadsheet with daily totals for all ad spend vs all leads vs all sales. Calculate your ROAS and CPA from there.

https://help.kajabi.com/hc/en-us/articles/360037178413-Meta-Pixel-With-Kajabi

https://developers.facebook.com/docs/marketing-api/conversions-api/