"playing for tier1 team and going to school will also disrupt mouz prac schedule too right" you are absolutely right. In one of post-game interviews for ESL pro league, karrigan himself stated in a bit of a ranty underlying tone that mouz can't practice as much as other teams, due to bymas having to attend school.
I think even Bymas was reluctant on joining a serious T2 team for a long time(as he said he did have a offers to join serious T2 teams when he was 16) due to school commitments. However, with pandemic lockdowns I think he fell a bit of under an delusion that due to LANs being cancelled and everything going online, he could manage both school and online cs. However, he probably underestimated how badly online CS would be saturated with events too(one week they playing DH qualifiers, next week they playing ESL pro league etc. + they still have to practice). If mouz starts trending down again, I think bymas will definitely be cut from the main squad, because he is definitely a part of the problem for mouz due to them not being able to practice as much(Bymas still has 2 years of school left for him, so this situation would definitely not be feasible for mouz long-term)