The rules have already been in place for the last two seasons, just with a transition period where the limits have gone down by one every year.
2022/23: maximum of 8 played loaned
2023/24: maximum of 7 players loaned
2024/25 onwards: maximum of 6 players loaned
Mind you those limits only concern international loans and also exclude homegrown U21 players. So for example PL clubs can still loan out as many players as they want within the UK.
Feck knows how my club are going to deal with these limitations. The loan quota is filling rapidly and there are still more than half a dozen foreign youngsters at Chelsea who still need loans.