They want to portray Kyungsoo as a selfish guy who left EXO for acting career.. I always think he enlisted because he needs to come back before beagle line enlists which has 2 main vocals so that there can still be main vocal for the group..

IDK if anyone thinks about this, but everytime I try to check the timeline of events, there is a great possibility that 92 liner and his enlistment will overlap and that there will be no remaining main vocal for EXO if that happens so he enlisted..

And the timeline seems right, he will come back in 2021 and beagle line will enlist..

basically.. Kyungsoo and Minseok will fill in 2021-2022..
I still hope Sehun will do his solo album and Kai has possibility to release his 2nd album if the KOLO1 has good reception all before they enlist.. When both enlist, Jun and beagle line already discharged..

This is purely my thoughts... We don't really know what happened in 2019..