You can have a perfectly legitimate and audited set of accounts that the PL still deemed to be in bad faith and misleading (In terms of how you chose to account in order to circumvent their own set of rules).
If you sell shirts at the stadium shop on matchday, that could be deemed matchday revenue. However, you could alternatively just attribute them to merchandise regardless of matchday. Neither is wrong, but the PL might try to argue you've chosen a specific categorisation to give a skewed picture that favours FFP. That becomes very subjective very quickly and any club on their right mind would always choose to account for things favourably. I seem to recall Liverpool declaring huge figures for infrastructure consultancy and the PL not batting an eyelid.
As an example, you may have an internal team working on infrastructure improvements and their costs are attributed to infrastructure. The PL may take a view that they were just regular staff with a whole range of duties not attributed to infrastructure projects.
There is nothing illegal in the accounts as there can be many ways a company chooses to categorise its finances, but the PL make specific exemptions for some costs and not for others. So then it becomes a matter of the PL viewing things one way, and the City viewing them another.
Another example with a multinational might be that a department in the USA is paid as USA employees, perfectly legitimately, but once in a while they do some work for the UK branch and countercharge the UK. The countercharge might be far less than it would have cost to employ folks in the UK directly. Is this a form of disguising your real costs? I would say no, it's simply how multinationals work by using the most favourable country to gain the best tax advantages, labour and materials costs. Would the PL be irked by this? Very probably.
As for some additional damning evidence... disclosure will reveal each other's hand, so at this stage it would appear neither side has conceded and settled. It would appear both sides have maintained their stance in full knowledge of each others evidence and arguments and await the panel's decision. That really does suggest there is no smoking gun or very damning evidence, only a tight set of subjective interpretations. We can't know that for certain, but it seems a reasonable interpretation in the absence of no settlement or major leak.