With both Atletico and Barcelona improving and dropping so far, the reality is that they still have a chance of finishing in the top four, so if it was just about overtaking it would be fine if they could finish in the top four in the end.
Sure, both Atletico dan Barcelona still have an opportunity to be back at the top four on the table. Point gaps among the teams in 4th-8th aren't quite small, their positions can be changed in 1 or 2 matches only. I am not surprised if Atletico or Barcelona suddenly is in the top four again in the next month (January). I assume Rayo Vallecano will be out of the top four soon because they may lose points against Atletico, Barcelona, and Real Betis in January. It is a real chance for Atletico dan Barcelona to be back at the UCL zone.
Check La Liga fixtures in January 2022https://www.footballwebpages.co.uk/spanish-la-liga/fixtures-results/januaryBasically these two teams have a high winning mentality and with the current points difference and also, the league still has at least half a season to run. So it is very possible that both Atletico and Barcelona still have a chance to end the season in the top four. The three teams currently above Barcelona who are very likely to be eliminated are Betis, Rayo Vallecano and Real Sociedad, although they are in a better position than Barcelona right now but in reality they are not strong enough to keep their position. I'm sure about that, because the statistical records of their goals and concedes are not much different and even almost the same, then I still believe that a team with a big name and a high winning mentality will still be able to take over the best position in the near future until the end of the season.