Answer
A Zoom license of TU Wien (Education license), which has no time limit and is suitable for meetings with up to 300 people, can be activated via TUWEL by adding the Zoom-activity to a TUWEL course and opening it. If there is already a Zoom-activity in your course, it is sufficient to open it. You can find instructions on TUpeerTube.
If this is not sufficient for your purposes and you need to upgrade your account, please contact the TUWEL support.