GA4 Tracking on BigCommerce and WooCommerce

We are currently experiencing issues with the Google Analytics 4 (GA4) tracking on two e-commerce platforms; BigCommerce and WooCommerce. Both sites are tracking events but are failing to accurately track average engagement time per session, sales, and revenue (BigCommerce) and showing significant discrepancies in tracking, including conversions (WooCommerce).

We seek an experienced GA4 expert to diagnose and resolve these tracking issues.

Scope of Work:

BigCommerce: Troubleshoot and rectify issues with GA4 tracking, specifically with average engagement time per session, sales, and revenue. The solution must be configured using custom scripts, as we have a custom checkout which does not support BigCommerce's native integration.

WooCommerce: Correct discrepancies in event and conversion tracking, which is currently implemented using Google Tag Manager (GTM).

Key Tasks:

1) Initial video screenshare meeting to discuss the issues in detail.
2) Conduct thorough GA4 diagnostics for both websites to identify potential causes of the tracking issues.
3) Develop and implement solutions to the tracking issues, using custom scripts for BigCommerce and GTM for WooCommerce.
4) Validate that solutions are correctly capturing all required data and are accurately reporting in GA4.

Price is a placeholder. Please share your proposals.