Yes it's not easy for Arsenal to reach the final, I'm not an Arsenal fan but for now I love this team, they really worthy to be in the final, also Premier League is the most competitive league but Arsenal can still stay at the top of the standings. For the upcoming matches in the next few days. To be honest, I also agree about Barcelona, they are the strongest team at the moment, they have great players but back to the coach's strategy.
Arsenal are focused on the Premier League, I'm sure they don't think much (if not at all) about the Europa League. As for Barcelona, even if it is a favorite, the bookmakers quotes are simply ridiculous:
UEFA Europa League 2022/23 - FC Barcelona reach Round of 16?
Yes - 1.57
No - 2.25
Being able to beat underdogs with a great percentage of efficiency is certainly good, but in big games Barcelona are weak this season.
It is true that Arsenal will likely not focus on the Europa League considering their points gain in the regular league is getting easier to be shifted by some of their rival teams and they certainly don't want to lose their current regular league title, having last won in the 2003/2004 season.
Regarding the bet on Barcelona qualifying for the playoffs, I think the bookie is really trying to make gamblers doubtful about the odds. But if I were in that position I would still bet YES on Barcelona because they have proven their consistency so far.