Although Real Madrid has now added mbappe to their squad, who will make them stronger, if Barcelona doesn’t add more effort to get more talented players that will face the performance of Real Madrid, I think they will definitely maintain that second position, which means winning the title might be so hard, but let's see how the transfer market will be before the season.
What you said is the reality. What Barcelona needs to do is to focus on enriching its squad depth to be prepared for the next season which is obviously going to be a tough one as upcoming clubs are warming up to take the space, clubs like Girona and Leverkusen did well in their own table leagues while other elite clubs are already gingered to work harder next season hence the change in managers currently happening across the clubs and the reformation some of those clubs making right now. So Barcelona must join the train to and make some tactical decisions concerning their squad depth to make them more fierce.