For non related parties (which Etihad are) the onus will be put on the PL to prove its not Fair Market going forwards not on the club to prove it is. So how can the PL judge what value a private company place on a deal.Just going back before 2021 rules where sponsor are still have to be fair value you can't have Etihad sponsoring us for 200m a year!
The bigger one is the loans from owner being 0% it got to be fair value where normal would be around 5%
Owner/Director loans will become related party transactions - which PL will have to look at value plus interest rates. Remember under FFP owners were allowed to put so much a year into the club (30 ml IIRC - although that might be per 3 year accounting period). So I assume they will have to look at values above what all clubs can do without penalties and also apply a notional interest rate of 8 to 10 percent.