That's right, losing or winning won't change Barcelona's position. and I think Xavi's goal to bring Barcelona back to the game has been achieved. at least this season Barcelona did not appear to disappoint by being in position 2.
Next season Xavi with better players in the Barcelona squad, I think he will be able to provide better quality.
In my opinion, Xavi's job was good to bring Barcelona to finish in the 2nd standings, it means that things are getting better for now, so the final match with Villarreal even if they lose will still be good for Xavi.
I agree with you Xavi will be more prepared for next season, by starting a new career the squad will be shown to remain impressive and next season they will still be able to compete in the UCL with manager Xavi.
Of course Xavi will prepare the team for next season, Xavi has founded a good rhythm in the squad. Some new players are Xavi targets to fill his team squad, of course there are some players who will leave Barcelona. Xavi's formula will be seen next season, he can choose the players he likes to bring to Barcelona. We will see how far Xavi can bring Barcelona in competing with other elite clubs.