The teams from Laliga performed quite impressively in the Champions League where 4 representatives from Laliga were able to end the last match in the group phase as group winners such as Real Madrid who led Group C, Atletico Madrid who led Group E, Real Sociedad who led D and Barcelona who led Group H. It seems that if you look at the strength of these 4 teams, I think they will succeed in bringing the UCL title home to Laliga because they have the most representatives who have qualified for the round of 16. And maybe only Sevilla failed to advance because they weren't very strong this season.
Apart from that, of the Serie A representatives, only AC Milan failed to advance to the round of 16 because they lost in goal productivity to PSG. Of the Premier League representatives, only Arsenal and Manchester City qualified, while Manchester United and Newcastle United failed to advance to the next round. From the Bundesliga, only Union Berlin failed to advance. I think this is quite an interesting season for the defending champions, namely Manchester City, because they have opponents who are tough enough to stop them from winning the title.
I think that's just your assumption because if you look at last season Serie A had 3 representatives who qualified for the last 8 but in the end they failed to win the title because Manchester City managed to beat Inter milan in the final match. So, it is not impossible that this will also happen to the Laliga teams that qualify for the next round because we will see how strongly they compete in the knockout round. However, they have greater opportunities compared to teams from other league. I will not measure the number of delegations from each league that qualify for the round of 16 because team from other league are quite strong this season, such as Bayern munich.
It's quite a shame that AC milan didn't qualify for the round of 16 because they are a team full of experience but they failed big in the Champions league this season. AC milan fans were both disappointed and happy because they were disappointed to be eliminated early and a little happy because they could join the European league. As said by other users, Ac milan will also easily lose in the European league because AC milan has been underestimated this season because of their instability in either Serie A or the Champions league.