Looking for facebook/instagram ads expert

Cover the following scope for our project:
Ad copies
Ad creatives (images)
Continuous optimisation
A/B testing
Retargeting
Audit website and provide suggestions to increase conversion rate
Campaign monitoring
Provide ROAS Guarantee after 4 weeks of running ads
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We already have implemented pixel/events on our website and have a facebook ads manager account setup.
Long term project. Fee paid monthly.