These after parties could sometimes last an hour after formal lessons had ended and I could hear kids talking and laughing together in an organic way. Something I never hear when my kids video chat with one other friend "head to head".
So, my recommendation is find a way for kids to interact in organic groups.
After the teacher had done their lesson and left, my guess is between 8 and 12 kids regularly stayed to goof off.
I think parents will respond better to "virtual recess" than "after party" :-P
*ymmv, but it seemed to work reasonably well for my kid and his friends 6-9 yr old age range.
We have to carefully monitor her screen time because online socializing is very addictive, especially for children. They can spend morning until midnight on their phones if you let them. On the plus side, it's a good way to train discipline - they can look at their phones after homework, a shower, cleaning the dishes, and only until 10 PM. Just sneak a new chore in there every month once they do the previous chores automatically.