I do not believe that Real is afraid of Sevilla's persecution. Everyone understands that Sevilla does not have the resources to be successful until the very end of the championship and it will have more points loss than Real Madrid. But the failures of Atletico and Barcelona please Real Madrid, since these teams are its real rivals, but have already fallen behind too far and have no chance of returning to the fight.
Real Madrid will not be afraid because their initial enemy when they set foot in La Liga was Barcelona. But Barcelona today is not the Barcelona we saw a few years ago. They don't seem to have anything to be proud of when they play on the pitch. The enthusiasm of the supporters (including myself) is getting worse day by day because indeed everyone realizes what is in front of him is not a scary club. Instead, Barcelona became the subject of ridicule from the audience.
Because so far it is Sevilla who are able to put pressure on the standings, automatically like it or not, Real Madrid will have to face them later. It's still a long time and maybe Sevilla's performance will continue to improve or vice versa.
Real Madrid overtook Barcelona last season but lost 2 points to Atlético
I do not think that deep historical background has any meaning in a particular situation - Atletico and Barcelona lost the competition this season and are not dangerous for Real now. Sevilla is formally close and may even overtake Real, but the chances of this are extremely small, the bookmakers which are responsible for their forecasts with money estimate the chances of Sevilla as very small.