Author here.

Jitsi is compatible with e2ee. For group calls, almost all of the work for e2ee is in the clients. And Jitsi can work with such clients.

I think Jitsi group calls can be end to end encrypted, provided all participants use Chromium 83, per https://jitsi.org/security/.

AFAIK this was a work in progress[0]. I am not sure what the status of this is now.

[0] https://jitsi.org/blog/e2ee/

AFAIK it's E2E for 1:1 video chats, but not when more are there.

Jitsi does support e2ee for groups as well https://jitsi.org/e2ee-in-jitsi/