It will be difficult for Chelsea to qualify for any European competitions this season, Chelsea's inconsistency will not allow them to gather enough points that will qualify Chelsea for any of the European competitions next season. Chelsea should focus on winning their matches so that they will not be relegated this season, next season they can challenge for the title or qualify for the uefa champions league.
Lol the first part of your post is ok, it is true that Chelsea has no reason to believe they could have a chance to qualify for any of the European competitions. But why should Chelsea be concerned about getting relegated? Like, what are the indicators as of now in the table that you see as being a threat for Chelsea to be relegated by the end of the season? I think every single post should have a least amount of substance and effort put into it. That's why I would kindly ask you to provide the substance for the idea that Chelsea should put the whole focus on not being relegated.
No one will ever bet on Chelsea to win the Premier League title at the end of this season and even if Chelsea makes many changes in the teams and hires many players to have better performances, I still don't think if they can have any good chance for winning the title and as you said the best thing they can do at the end of this season is to just get the Europe League ticket for the next season which still hard for a team like Chelsea considering the results they got so far.