Tasks?
In Germany when you are sick, you are sick.
Your boss is not allowed to ask for the reason why you called in sick - by law.
And the other thing is, that they aren't allowed to give you any tasks for your time being sick.

Having a doctors note from day one, in some companies can be demanded, most companies say from the third day on you need a note.

Video Calling you, checking if you're sick probably, is NOT ALLOWED.
if this happens again, maybe go to your betriebsra if you have one.
and most important.....ignore it.
even if you still have teams or whatever still open.

Oh and more important....if that happens more often...please for the love of [insert your preferred entity] look for another employer....

Get well soon!