The UCL Semifinal match will not be easy but we also cannot see the match in the domestic league and the last few matches as a reference, we have to look at the overall strength of the team and the strength of PSG and Arsenal I think is quite balanced so that it makes the match more fierce and also the same possibility for both teams to be able to qualify for the Champions League final this season.
What's interesting is that Arsenal and PSG are two teams that have never won the Champion League trophy so this season they have the same motivation and ambition.
They have never won Champions League title and have to fight and eliminate each other for a final match before they can play and win in the final match. They are both strong and very ambitious in semi finals to firstly join a final match and secondly win a first ever UEFA Champions League title for their club. Arsenal and PSG are different in their club development and financial budget already spent last two decades but their purpose is the same: the title, first ever.
There is no point in assessing the strength of teams based on matches that mean nothing to them. PSG are already champions, and Arsenal understand that Liverpool is unimportant to them, so they are preparing only for the Champions League matches. Another thing is with Inter, they need to think about Serie A matches, because they are fighting for the Scudetto, but at the same time they have already lost several games in a row, they also lost to Milan in the Cup, and it seems that Inter is in a difficult psychological state, which is only good for Barcelona, because they are in a positive mood after beating Real in the Cup final.
Both PSG and Arsenal completed their task in their domestic leagues Ligue 1 and Premier League and they decided to focus on more important matches, firstly two semi final matches in Champions League and if succeed a final match later. When a season has only some remaining matches but decide whether they win titles or not, hard but wise decision must be made.
It does not mean by focusing on Champions League, they will win this title because only one club can become a champion at the season ending, but focusing more on this league and maximum three remaining matches will increase their chance of winning this big and precious trophy.