Monsta X , Stray Kids & Ateez have more ifans than korean fans so they were never part of korean chart competition.
When do you think the competition for bg in korean charts stopped ? I say after 2018/2019
I also think Melon chart is not relevant as "what the public listen to" as I think it's driven by fandom (except for few idols) more than ever
Seeing how a lot of Korean switch to youtube music I think they have more choices as to what app they can use
Spotify launched in Korea in 2021 and Youtube music in 2018 (and it seem that YT music is growing fast)