Even if you believe Barcelona has a strong squad that would have challenged PSG in the final if it was Barcelona that played against PSG in the final, I want you to understand that this said PSG squad beat and knocked out Liverpool from the UEFA Champions League competition, who were once the favorite to win the UEFA Champions League trophy, and Barcelona could have come up short against Liverpool if they had played against Liverpool in the UEFA Champions League competition, so I believe PSG would still beat Barcelona in the final if it was PSG and Barcelona that played in the final.
It's not how many star players can affect the result. Although normally the squad affects the result. Real Madrid has a good squad, but they failed early and couldn't reach the final. Even in the Coppa del Rey they failed, this is something that can't be denied, sometimes, who don't have star players can also become champions as long as they are able balanced their playing strategy with opponent's playing style and can take advantage of any moment to score goals. Inter failed in the final, not because they didn't have good players, but in that match, Inter was under their performance.