A temporary solution is better than none or some for which you then have to pay a lot of money (termination of the contract).
There are rumors that Nagelsmann will lead the team in the summer, and now he wants to rest until the end of the season (or just does not want to get under the Real Madrid ice rink). But there are also rumors that PSG also want to sign Nagelsmann. Will he, like Mbappe, negotiate for himself the best conditions from two rich clubs? Cunningly!
Chelsea's season is almost over. They won't play champions league football next season unless they win the champions league this season because, with the current position they are in and with the form of the teams above them, there's no way they can climb the top four even if they win all their remaining matches in the league. So I don't see the point in bringing a manager that you will give a full-time contract if he does well and there is no reason to bring a manager like Lampard as Interim during this difficult time in the season.
They need a tactical manager that can at least give them hope of winning the champions league since that is their only hope, Im sorry but Lampard is not that kind of coach.
I get it, they don't want to rush and sign a manager on a permanent deal that they will regret later but they should have looked for a new face with a new ideology.