I dont see why this is a 'loophole' Chelsea are taking advantage of. There is no 'advantage'. They have assumed a massive amount of risk taking on so many players on 8 year contracts at massive money. If all these players hit the mark, then they should benefit from the risks they took. However if these players dont hit the mark , and they get another round of Lakaku's, Haavertz, Pulisic, Koulibaly, Cucarella - a combination of outright disasters and underperforming players, then they are in big trouble. They will be in such a bind that will last multiple years, they will be constrained by having underperforming players on the wage bill with no real way to move them, other than perpetual loans, whilst also still being booked under FFP accouting standards, which leaves less room to bring in replacements for any players that underperform.
They also used a factoring company to finance the Enzo deal. So the 107m fee is the official fee, but there will be associated interest payments on the fee. The out of pocket cost for Chelsea is going to be above 107m.
I dont see why these 'loopholes' need to be closed. If Chelsea want to bet the house on the current round of signings, they should be able to. Its their neck on the line