At the end of 2021, BTS had no equals on the face of the earth.
Everyone , except the two I will cite, was either its friend or at least was neutral.
Only The Weeknd, whom, to this day , has not met BTS and tried to undermine it by inviting Jennie (BlackPink) to his show, and BTS's long time archenemy IU opposed it.
However, with few allies, the Weeknd could not do anything to BTS, and IU only had influence within South Korea, although that proved to be fatal. No one can claim more credits bringing down BTS than IU.
In 2026, it will face opposition all around the world.
Most of its friends have moved on or would be its rivals.
Even in hybe, SVT, NewJeans who-Hybe-will-debut and others will try to fight BTS.
Jungkook tried to rein The Kid Laroi but if he becomes successful who knows how he will behave against BTS.
IU personally will lead the entire Kakao Entertainment to fight BTS herself.
Assuming BTS can silence NewJeans, etc and IU, it will face the torrent of newer acts which get established 2023-25.
None of the erstwhile allies will come to help it since it is no longer dominant.
When Napoleon was doing well, he crossed the Rhine like a neighborhood stream, crossed the Danube whenever he felt like it and he crossed the Niemen (Neman, Nemunas), which at that time was the border between Western Europe and Russia, at least once. However, after his 1815 return, he couldn't even cross the Meuse (a river which flows through what is now Belgium).
Assuming BTS beats the iron ring of containment formed by NewJeans and IU, it will have to fight the new crop of artists who took power.
Then it will have to fight Morgan Wallen, who was a non-entity when BTS had conquered the world but is now a big force to be reckoned with in the country music.
Assuming BTS beats all of them, it will have to fight the established stars who will not allow another intrusion like 2020-22.
Once power is lost, it is impossible to get it back. Even adele had a hard time getting back to power in 2021 because BTS had become the dominant act.