Who can be landing page configured to be open a new ticket page?
and disable view ticket page and initial page?
This is not a feature in osTicket at this time. You would have to edit the core files to achieve this.
ntozier how to do that? have agent login page as landing page
That is not something that I have ever tried to do, so you would have to dig into the code see how things work and then decide how you want to code/implement the change.