وَبِالْجُمْلَةِ الْأَحَادِيثُ فِي هَذَا الْمَعْنَى ... مُتَوَاتِرَةُ الْمَعْنَى
Taken together, reports on this subject are recurrent in their shared meaning.
Tawātur maʿnawī is the convergence of many narrations, despite differences in their wording or incidents, upon a common substantive meaning. Here that common meaning concerns the reality of barzakh questioning, punishment, and comfort.
This does not declare every individual chain, phrase, incident, or disputed detail to be mass-transmitted by itself. The evidentiary status of the shared conclusion and that of any isolated report should remain distinct.