Real VNC Server is not running on Kubuntu 22.04

I need to survey remotly 2 small computers for home automation where I installed Ubuntu 22.04. On both it is possible to install the VNC Server by the script. Deb install always claims missing dependencies. Server shows up as un icon and after start it claims the admin password. After typing it nothing more happens. Also the different command line starts works only so far that one version claims for an offline key that i do not have and i do not know how to get it. Is this problem known and resolved, as without a solution I would not go for a purchase after the trial phase.