Although Lewandowski has reached an agreement with Barcelona to stay with Barcelona until the end of the season or one more season. But Barcelona must move quickly to find a replacement, Barcelona is currently eyeing Newcastle United striker, Alexander Isak, and Viktor Gyokeres from Sporting CP is a more affordable option with a cheaper transfer value.
Barcelona management will not take the risk too quickly to find a replacement for Lewandowski in a financial condition like this. As long as Lewandowski can still be relied on, Barcelona management will look for a replacement player with an easier option such as a player who has free agent status. And in my opinion if Barcelona is eyeing Alexander Isak, it is just a rumor. On the one hand, Newcastle will not release the player at a cheap price and while Newcastle currently still needs the player. So at this time Barcelona can only survive with the existing players and look for a replacement player slowly without rushing which can put more pressure on Barcelona's finances.
Yes, you are 100% right and I also share the same sentiment as you bro, Barcelona doesn't have the financial capacity to sign isak from Newcastle because he wouldn't come cheap even though Newcastle united decides to let the player go, but as for now, Robert lewandoski is still the main man, so I think that this should be their headache in the summer transfer window not now that the season is getting heated.
But if Barcelona can tie Robert lewandoski to one more season at the club aside this present one, it would be very nice because they are not that sure that the attacker they are going to sign is going to hit the ground running, so if Robert lewandoski is still at the club, he is definitely going to be helping the team till the player is ready to deliver, or he can equally play alongside anyone that is signed eventually if he is still at the club next season, but if Barcelona really want to compete against the likes of real madrid and atletico madrid next season, they must splash the cash on quality players, not all this free transfer they are aiming at.