Choose how hosts are assigned
Three ways to share a slot, and the reason the third only appears sometimes.
Three ways to assign a host, and the choice has a much larger effect on availability than people expect — particularly the second one.
All hosts together means availability is the intersection of everyone's calendars. With two people that is usually fine. With four it can produce almost no slots at all, and the link looks broken when it is doing arithmetic.

Reference
Random pick, to spread the load
Convarza picks whoever is free, spreading bookings across the hosts. The default for a sales team where anybody can take the call, and the option that maximises available slots.
All hosts together, for a panel
Everyone joins, and availability is the intersection so nobody is double-booked.
Check the resulting availability before publishing. Four calendars intersected can leave you with two slots a fortnight.
Let the invitee choose, when it genuinely matters
Right when the customer has an existing relationship with one of your people and would be annoyed to get somebody else.
Notice when the third option disappears
It only shows when there is more than one host, because with one host it is not a choice.
Expect adding hosts to shrink availability
With "all hosts together" especially. Add the fourth person and check the link again before you assume it still works.
Remember what an agent can do
An agent can create a link hosting only themselves. Adding other people is a manager or admin action, and the page says so rather than showing a control that would be refused.
Put it to use
Open the link and count the slots offered over the next two weeks. If it is fewer than you would be happy to offer a customer, change the assignment mode before you change anything else.
The parts people get wrong
- An agent can create a link that hosts only themselves. Team links are a manager or admin action.
- With "all hosts together", one host's busy calendar limits everybody. That is arithmetic rather than a fault.