as you said, if Arsenal really need a change in their title pursuit strategy, that should be prioritized and from my opinion, if they really want to get the EPL title, they should try to prioritize matches in the EPL and consider the UCL as a second match that doesn't need to be prioritized.
and this kind of method can make Arsenal closer to winning the EPL title and if Arsenal succeeds in getting the EPL title, the mentality of the Arsenal players will definitely become more confident.
That's just it, they should just focus on the English premier League as there main targets and stop diverting there attention to other leagues, though I'm impressed with there performance this season even if they did not win the premier League but they mount serious pressure on Manchester City before they manage to win the premier league, so since they no that they are not the right candidate for the champions League trophy they should concentrate more on the premier league they have the performance to win.