The article is just not worth fretting about at all, it contains a load of nonsense
For starters, it's well documented the league have been supervising our spending for years and we have co-operated. If clubs feel the league should have punished us or stopped us spending, then their legal action would be against the league not us. We've done what we've been allowed to.
Secondly, the basis for the purported legal action is presumably that we should've been docked points or should've had a transfer ban which would've resulted in worse results and us placing lower. The fact is the PL rules around FFP don't prescribe set punishments for any breaches, just a range of measures. Since no punishment is specified how can other clubs claim that we OUGHT to have a certain punishment? Under the rules the PL can do what they like.
Thirdly if the claim is that we shouldn't have been allowed to sign players, how would they prove this harmed them? Anyone who knows anything about football transfers, and Everton transfers in particular, knows they are not guaranteed to make a team better. It would be total conjecture to say what would've happened if we were transfer banned. Maybe in that alternative timeline Tom Cannon has 20 goals for the season and we are comfortably mid table.
Lastly, the article goes on about all the relegated sides suing us for 100m each to compensate which is where they get the 300 MILLION headline, and that's plainly nonsense. The only team that could have any possible action is the one finishing 18th, for reasons that would be obvious to anyone barring, it seems, our friend Matt.