Félix, 23, has scored three times in his first two starts for Barça after joining the club on a season-long loan from Atletico earlier this month.
"When things are going badly in football for someone, you have to make a change," Félix said in an interview with Mundo Deportivo on Thursday.
"I did it before going to Chelsea [on loan in the second half last season] and now coming to Barcelona because it was not going well [at Atletico].
"I didn't adapt to the club's or the coach's ideas, but I always tried to do the best I could. I have had good times there as well."
Félix turned down interest from Saudi Arabia to wait on Barça's interest, with a deal eventually going through on the final day of the summer transfer window.
In order to get the loan over the line, Felix had to agree to a substantial wage cut due to Barca's financial problems.
"It's true I gave up a significant part of my salary, but I needed a change," he added.
"I needed to come to a place where I can play my style of football and I have always said I think this is the ideal place.
"Things are going well -- I didn't expect to start so well -- and it was an effort I needed to make to be able to find joy playing football again."
Those results prompted Barça coach Xavi Hernandez to claim his side are playing their best football since he took over in 2021.
"In terms of quality, I think he's the best full-back I have ever played with," Félix said of club and international teammate Cancelo.
"He has the quality of a No. 10. He even likes to play as a No. 10 and says that he will end his career playing as a No. 10 back in his hometown with his local club.
"He's an extraordinary player. He has added a lot to the team. Wherever he has played, he has brought so much and always won a lot of trophies."
Meanwhile, Alejandro Balde signed a new contract with Barcelona on Thursday, committing him to the club until 2028.
"I arrived when I was six or seven years old with the dream of reaching the first team," the left-back told reporters. "That dream has officially become a reality. It's been a long journey with a lot of sacrifices. I only have words of gratitude for everyone that has helped in the process.
"I hope to be here for many more years. I am only 19 and still have a lot to learn and improve. I will be 24 when it expires -- I will still be young."
Balde, who said inheriting Gerard Pique's No.3 shirt is an "honour, not an added weight," signed his new deal, which includes a €1 billion release clause, at an event with Barça president Joan Laporta.
Laporta thanked Balde's agent, Jorge Mendes, who also represents Felix and Cancelo, for keeping his player at Barça when he could have gone elsewhere for more money.
"Mendes is someone who knows how to combine the interests of both parties, even if that sometimes means making sacrifices," Laporta said. "We are grateful that, in addition to defending the interests of his players, he always takes into account Barça's interests."