diff --git a/changelog.d/6233.bugfix b/changelog.d/6233.bugfix
new file mode 100644
index 00000000000..0c415e1078a
--- /dev/null
+++ b/changelog.d/6233.bugfix
@@ -0,0 +1 @@
+Fix | performance regression on roomlist + proper display of space parents in explore rooms.
diff --git a/matrix-sdk-android/src/main/java/org/matrix/android/sdk/api/session/room/RoomService.kt b/matrix-sdk-android/src/main/java/org/matrix/android/sdk/api/session/room/RoomService.kt
index 0a495f35524..5dfb8961e3c 100644
--- a/matrix-sdk-android/src/main/java/org/matrix/android/sdk/api/session/room/RoomService.kt
+++ b/matrix-sdk-android/src/main/java/org/matrix/android/sdk/api/session/room/RoomService.kt
@@ -226,12 +226,19 @@ interface RoomService {
     ): LiveData<PagedList<RoomSummary>>
 
     /**
-     * TODO Doc.
+     * Get's a live paged list from a filter that can be dynamically updated.
+     *
+     * @param queryParams The filter to use
+     * @param pagedListConfig The paged list configuration (page size, initial load, prefetch distance...)
+     * @param sortOrder defines how to sort the results
+     * @param getFlattenParents When true, the list of known parents and grand parents summaries will be resolved.
+     * This can have significant impact on performance, better be used only on manageable list (filtered by displayName, ..).
      */
     fun getFilteredPagedRoomSummariesLive(
             queryParams: RoomSummaryQueryParams,
             pagedListConfig: PagedList.Config = defaultPagedListConfig,
-            sortOrder: RoomSortOrder = RoomSortOrder.ACTIVITY
+            sortOrder: RoomSortOrder = RoomSortOrder.ACTIVITY,
+            getFlattenParents: Boolean = false,
     ): UpdatableLivePageResult
 
     /**
diff --git a/matrix-sdk-android/src/main/java/org/matrix/android/sdk/internal/session/room/DefaultRoomService.kt b/matrix-sdk-android/src/main/java/org/matrix/android/sdk/internal/session/room/DefaultRoomService.kt
index 7a7804c3544..5e6d052443d 100644
--- a/matrix-sdk-android/src/main/java/org/matrix/android/sdk/internal/session/room/DefaultRoomService.kt
+++ b/matrix-sdk-android/src/main/java/org/matrix/android/sdk/internal/session/room/DefaultRoomService.kt
@@ -139,9 +139,10 @@ internal class DefaultRoomService @Inject constructor(
     override fun getFilteredPagedRoomSummariesLive(
             queryParams: RoomSummaryQueryParams,
             pagedListConfig: PagedList.Config,
-            sortOrder: RoomSortOrder
+            sortOrder: RoomSortOrder,
+            getFlattenParents: Boolean
     ): UpdatableLivePageResult {
-        return roomSummaryDataSource.getUpdatablePagedRoomSummariesLive(queryParams, pagedListConfig, sortOrder, getFlattenedParents = true)
+        return roomSummaryDataSource.getUpdatablePagedRoomSummariesLive(queryParams, pagedListConfig, sortOrder, getFlattenParents)
     }
 
     override fun getRoomCountLive(queryParams: RoomSummaryQueryParams): LiveData<Int> {
diff --git a/vector/src/main/java/im/vector/app/features/home/room/list/RoomListSectionBuilderGroup.kt b/vector/src/main/java/im/vector/app/features/home/room/list/RoomListSectionBuilderGroup.kt
index 70fb6988e85..01fced64891 100644
--- a/vector/src/main/java/im/vector/app/features/home/room/list/RoomListSectionBuilderGroup.kt
+++ b/vector/src/main/java/im/vector/app/features/home/room/list/RoomListSectionBuilderGroup.kt
@@ -71,7 +71,7 @@ class RoomListSectionBuilderGroup(
                         },
                         { qpm ->
                             val name = stringProvider.getString(R.string.bottom_action_rooms)
-                            val updatableFilterLivePageResult = session.roomService().getFilteredPagedRoomSummariesLive(qpm)
+                            val updatableFilterLivePageResult = session.roomService().getFilteredPagedRoomSummariesLive(qpm, getFlattenParents = true)
                             onUpdatable(updatableFilterLivePageResult)
 
                             val itemCountFlow = updatableFilterLivePageResult.livePagedList.asFlow()
diff --git a/vector/src/main/java/im/vector/app/features/home/room/list/RoomListSectionBuilderSpace.kt b/vector/src/main/java/im/vector/app/features/home/room/list/RoomListSectionBuilderSpace.kt
index 0e3f61e1865..362c4461156 100644
--- a/vector/src/main/java/im/vector/app/features/home/room/list/RoomListSectionBuilderSpace.kt
+++ b/vector/src/main/java/im/vector/app/features/home/room/list/RoomListSectionBuilderSpace.kt
@@ -332,7 +332,7 @@ class RoomListSectionBuilderSpace(
                 },
                 { queryParams ->
                     val name = stringProvider.getString(R.string.bottom_action_rooms)
-                    val updatableFilterLivePageResult = session.roomService().getFilteredPagedRoomSummariesLive(queryParams)
+                    val updatableFilterLivePageResult = session.roomService().getFilteredPagedRoomSummariesLive(queryParams, getFlattenParents = true)
                     onUpdatable(updatableFilterLivePageResult)
 
                     val itemCountFlow = updatableFilterLivePageResult.livePagedList.asFlow()
diff --git a/vector/src/main/java/im/vector/app/features/home/room/list/RoomSummaryItemFactory.kt b/vector/src/main/java/im/vector/app/features/home/room/list/RoomSummaryItemFactory.kt
index 9601ccf9147..9b0427792fa 100644
--- a/vector/src/main/java/im/vector/app/features/home/room/list/RoomSummaryItemFactory.kt
+++ b/vector/src/main/java/im/vector/app/features/home/room/list/RoomSummaryItemFactory.kt
@@ -207,7 +207,7 @@ class RoomSummaryItemFactory @Inject constructor(
 
     private fun getSearchResultSubtitle(roomSummary: RoomSummary): String {
         val userId = roomSummary.directUserId
-        val spaceName = roomSummary.spaceParents?.firstOrNull()?.roomSummary?.name
+        val spaceName = roomSummary.flattenParents.lastOrNull()?.name
         val canonicalAlias = roomSummary.canonicalAlias
 
         return (userId ?: spaceName ?: canonicalAlias).orEmpty()