I am not sure if Liverpool sold Mane because they felt they will buy Nunez to replace him. If it was what happened, it is a dump move by Liverpool and a let down to Mane. Just because Nunez scored good number of goals in an unpopular league doesn't mean that he is fit to replace Mane who has a very large work rate in Liverpool.
Actually, Liverpool's selling of Mane is a big mistake they made and I am sure they regretted it at one point or the other even if they are not going to admit it.
The another one mistake is Liverpool not want to extend Firmino's contract, he's only play as a substitute and he can score more goals than Nunez and Gakpo.
But the bad perform of Liverpool was caused by Diogo Jota and Luis Diaz long injury, the next season both of them will back. Liverpool will be solid because Salah will always play in right winger and Luis Diaz will play in left winger, I think the center forward would be Nunez or Gakpo, both of them will replace each other.
That's not the only thing that has made Liverpool decline this season, so that from the start of the season they didn't show their usual appearance. From the defense, midfield and front line they didn't play well, and what was more problematic was that there weren't any players who made the difference when they needed it. The absence of several main pillars also affected the team's performance. What I am focused on now is their midfield which has played far from expectations, when they receive attacks they cannot be a line that can cut off the opponent's attacks, and when they attack they cannot create a more diverse attack scheme so they are often broken by the opponent's defensive line.
I think the Premier League will be even more exciting next season and it is likely that the title race will become even tougher. Arsenal and Newcastle, who have performed quite well this season, will definitely make more thorough preparations. While Liverpool, Tottenham, and Chelsea, certainly do not want to remain trapped in their slump. Besides that, there is Man United, which has improved quite a bit this season. Of course, Man City is still the favorite because they have successfully defended the trophy for 3 years in a row.
I believe that the forthcoming season of the Premier League promises to be an exciting one for fans. Teams like Newcastle and Arsenal who have shown potential this season will definitely be inspired to strengthen their preparations and up the ante on their competitors. Despite possible setbacks Liverpool Tottenham and Chelsea will be motivated to recover and recapture their old greatness. The season long improvement of Manchester United only heightens the suspense. The domination of Manchester City who have successfully defended the championship for three straight years is difficult to ignore though. Their sustained performance places them as the favourites once more heightening the intrigue and excitement around the title race.
Now the competition is getting more interesting because more and more teams can provide competition at the top, Newcastle is one of the teams that has just joined the competition at the top, they even managed to be in the top 4 this season and will be one of the teams that will participate in Champions League. Meanwhile, the big teams that have always provided tough competition in the previous season actually experienced bad things because they experienced a lot of decline, like Chelsea for example. But I also believe that in the coming season they will show their best to be in the top teams.