Similar screens can represent different objects
Supergroups and broadcast channels can both use the channel constructor; inspect their flags. Basic groups have different administration and migration rules, and gigagroup conversion includes irreversible conditions. Names and member counts are not reliable type identifiers.
Topics belong to a chat context
Forum supergroups organize conversations into topics with specific creation and administration rights. A bot’s threaded mode has separate settings and conditions; it is not interchangeable with an ordinary group forum.
Direct channel messages have their own structure
Enabling channel messages associates a special monoforum. Its conversations are organized by user using fields such as saved_peer_id, unlike ordinary forum-topic threads. Message links, routing and permissions must use the actual direct-message chat context.
Modeling recommendations
Retain account, peer, topic or sub-dialog, and message identity separately. A unified UI may sit above type-specific permissions and routing. After migration or conversion, update links and cached identities before allowing further actions.