It is true that Aston villa has achieved a great feat with unai emery by getting champions league football, but for me this is not enough reason to grant him a 5 year contract. Not to disregard the coach technical prowess, just what I do feel. The contract seem like a rush
Two years ago, when Aston Villa was coached by Gerrard the team finished 17th and struggled to stay out of the EPL.
In two years, Emery has turned an EPL outsider into one of the strongest teams not only in the English league, but also in Europe.
Aston Villa took 4th place behind only the strongest teams in the world Manchester City, Arsenal and Liverpool and this despite the fact that the transfer costs of Aston Villa were much less. In addition, Emery led Aston Villa to the Champions League after 42 years! The last time Aston Villa played in the Champions League was 1982.
I think that's more than enough for the Aston Villa management to give Emery that kind of credit and maybe he can build a team that can compete with Manchester City and Arsenal on equal terms.
To be fair, Unai Emery has been showing how great he is in many clubs before as well. He was great at Villareal too, that team isn't a team that anyone trusted to do well at all and he took that team and made it quite successful, better than what was expected of him.
I think it is quite clear that he is a great manager and not sure if his style would work with bigger clubs but he has done quite alright with bigger clubs too, Arsenal and PSG is in his CV and it wasn't that bad, he is even better since those days of course. I think he may have signed a deal, but I do not think that he is going to stay for the whole five years, if he keeps doing this great, some big team would be willing to pay the fee and just get him eventually.
Emery has a contract until 2027 and that's a decent term, and now they have extended it for another 5 years and I think he still expects to work at Aston Villa until the end of his contract, because as you rightly pointed out he works better and achieves more success at medium-sized clubs like Sevilla, Villereal or Aston Villa than at top teams like PSG and Arsenal, although there he has shown good results and here I agree with you too.
Now Emery has a task to keep the main players of the team, which now there is interest from top clubs.
It is written that Arsenal are interested in Douglas Luiz, who now instead of Wally Watkins is one of the best players of Aston Villa and Arsenal are looking for a replacement for Thomas Partey, who is likely to leave the team.
I think Aston Villa need to keep him if they want to perform as well as they did this season next season.