Ventura download completes but install doesn't follow

First of all, you did not say how long it was "stuck". In my experience my downloads typically take about 45 minutes or so and the installations take another 45 minutes or so with several automatic restarts. The download time will vary depending on the speed of your internet connection. If the installation process has been stuck for two hours, for example, then there is a problem with the installation. Typically the problem is that the downloaded file is corrupted and cannot successfully install. The solution is to put the old file into the Trash, empty it and then do a new download using a wired Ethernet connection, not Wi-Fi which is too slow for these very large downloads. I hope that works for you.