Multiple GA4 data to Big Query to Data Studio

We have a project to centralise Google GA4 data from 14 website properties (smallish, sites; between 10k pageviews to 30k pageviews per month size). We need data in BigQuery, to be available in Data Studio to run reports on all sites for Traffic Origin User Acquisition Traffic Acquisition Conversions and Goals Performance Click to Call Click to Email Form Submissions Top Performing Sites By Conversion / Goal By Engagement Engagement & Media Files Downloaded Videos Watched Pages Viewed, most engaging content All GA4 sites are connected via GTM, and have standardised events and custom dimensions. We are also familar with Data Studio, So this work will be mainly about connecting BigQuery up to the properties and presenting the data to be ready in Data Studio. Some help in Data Studio may be required, however DS is not the primary skillset we need. I would be keen to respond only to messages from experts who can quantify how long the above work will take them / provide a reasonable billing estimate. Pls can you message me back with a. an estimate of how many man/hours you expect this project to take / i.e. a billable estimate b. your experience with GA4 c. your experience with BigQuery we are a specialist marketing and web development agency with over 300 hosted clients, and have a regular flow of projects and limited resource internally - so a long term partnership would be welcome to support us