Regarding school attendance and grades, I can see merit on both sides of the issue, but 20% is pretty high.
Certainly those who could attend but don’t, should have some penalty, but those who stay out because they are sick should not be punished as long as they make up the work.
Having attendance count for 20% of the grade, automatically punishes those who miss school for legitimate reasons. Maybe a little praise, like an award would be a better way. Those who have good attendance may be blessed with better immune systems than others, or they may be attending even though they are sick and spreading it to others.
A blanket 20% for attendance reminds me of “Zero Tolerance” policies that sometimes blindly punish the victims along with the perpetrators, simply because they were “Involved”. I think a little investigation and discretion needs to be exercised by schools in both situations.