It can be true, they need a new striker for another option in the attacking line. When Lewandowski can't perform well, Felix can be the option to strengthen Barcelona attacking. However, considering the last performance of Felix when he joined Chelsea, I'm not sure Felix is strong enough to be the mainstay player for Barcelona. He is still young, but he isn't a typical player who can maintain his good performance a long time. He is very unstable player.
I think Barcelona has no other option, they take a loan option for Felix because Barcelona has limited money. If Barcelona has bigger funds, I'm sure they will choose other striker who has more stable performance like Lautaro Martínez or Victor Osimhen. So, it is very obvious that Felix is just for a short term solution for Barcelona attacking.
Actually João Félix is not center forward and can't replace well with position from Robert Lewandowski have underperformance or absent for Barcelona, when playing second half season for Chelsea, João Félix put as second striker and some time played in left winger position and he is not as center forward player typical. Current transfer from Barcelona as free and loan due financial problem make Barcelona hasn't option for buying top players.
João Félix have made debut last match with Barcelona but he not played full and waiting when get starting line up for playing in the first minute will give more contribution for Barcelona or not? João Félix have loyal for agree 50% salary cut off and Xavi Hernandez have looking potential from him how to back to the top performance with Barcelona.