Way back home was the 2nd song to be accused (and honestly I think even some people accusing it finally admitted it was huge eventually because it was really really huge), first one was Nilo's Pass by. Anyway the problem weren't these 2 but after these kpop fans started to use the sajaegi argument against any song coming from a soloist that blocked their favs. In 2019 and the first half of 2020 there were like 10? different songs accused of sajaegi and some of the accusations really made no sense.
However, I think that Melon didn't change the chart for this, this is a personal opinion and I could be wrong of course but I'm almost sure it was fandom streaming. In that moment it was becoming worse with fandoms becoming stronger and Mr trot happened in early 2020 and their singers were starting to chart like top groups with big fandoms at night too. The 24h chart system doesn't really have any effect to stop the supposed sajaegi, but it would end the realtime chart which was where the fandom streaming was reflected. A big change like that was also the perfect moment to say the bullshit that they were doing it to stop sajaegi so people would praise them but if you think about it a simple chart system wouldn't change "bought" streams in any way. Back then I personally was a good idea tbh, but I (and ig Melon, regardless of if it was because of this or because the sajaegi fr) definitely underrated the effect it would have in the charting of other songs.
Anyway looking at the fall of other charts, all this situation can't be just because of the chart system, it's just one of probably many reasons.