The OC client 3.x is not available for SUSE Tumbleweed. The latest version is 2.11 from the Suse standard repo-oss.
I tried to use the version from leap 15.4 on https://download.owncloud.com/desktop/ownCloud/stable/latest/linux/openSUSE_Leap_15.4/owncloud.repo. This one installs a bunch of ocqt5152-libQt5* dependencies but finally the client start fails with a still missing shared library libicui18n.so.suse65.1 which is not available for Tumbleweed.
Does anyone have a solution for this?