Currently there’s bug on latest htop version (3.1.0) in tumbleweed repo that prevent scrolling up (upstream report).
This bug is already fixed by upstream in version 3.1.1 and already release 12 days ago on upstream but it still not updated in tumbleweed repo.
How to request update for this package?
Updates normally reach TW fairly soon.
You could leave a note at https://build.opensuse.org/package/show/Base:System/htop for the maintainer of the package, but I don’t know it would speed things up…