I use XMPP with everyone who is willing to join and am available via text, e-mail and normal phone calls for those who don't want to join. However, it is a bit

I use XMPP with everyone who is willing to join and am available via text, e-mail and normal phone calls for those who don't want to join. However, it is a bit difficult with phone calls to countries outside of the EU: Sometimes I agree on using an old Skype account, sometimes I use my Nextcloud. In theory, XMPP could handle that too, but in reality, none of my XMPP-clients has a great call experience (same old 'XMPP-clients need some love' song).