Ramos may be able to help Sevilla's defense this season, but one cannot expect him to perform as well as before considering his age. As an experienced player, I am sure Ramos will play a good role in Sevilla's defense and he has proven it at PSG last season.
Ramos' performance is still good and he made 33 appearances last season in Ligue 1. Sevilla must give him trust or even a big role so that the team's mentality and defense are good. But I don't rule out the possibility that Sevilla actually also needs a good striker, clearly that could encourage more possibilities in their plans to win the match. La Liga has tough competitors, that's why Sevilla can't just carry out its mission without good squad depth.
Ramos is a strong defender, but we must know that he is no longer in their best form. I am not pessimistic about his contribution, he may bring positive impact for Sevilla defense line. However, with the current situation on Ramos, I don't think Ramos can significantly improve the strength of Sevilla defense. Moreover, Ramos often gets injured, he may be absent in some matches.
Sevilla actually has a good striker, En-Nesyri. This player often shows amazing contribution for Sevilla. But it is good if Sevilla has another strong striker, it will strength the power of Sevilla attacking. Anyway, there is something crucial for Sevilla, they lost their main goalkeeper. I think they also need a strong goalkeeper now.