Lampard may be a good coach, but we can't expect much from a team like Everton. Everton is a weak team. They have to spend money if they want to be strong. Talented players should be taken in the team. The players are weak but the coach is experienced, in this situation good performance is not possible. In addition to hiring experienced coaches, the coach should be given the opportunity to sort out the squad with the players of his choice. It will cost a lot of money.
Not one big team will agree to invite to the post of head coach, who has not shown results with weak and medium teams. If Lampard is a great coach, then when he joins a team, even one like Everton, he has to do the work so that the team plays better than before, that players give their all on the field in every match. He must motivate players to win. If there are no such results in the team, then this coach will not be interesting.
Yes even the top analysts after the news that he will sign for another 2.5 years as head coach will not be able to do much, but he will save the team from relegation. You can agree to some extent, of course, because he will really save the team from relegation, but it is unlikely to get the team to the top position, you need to make a lot of changes in the squad for that