Using QML TableView + HorizontalHeaderView with QSortFilterProxyModel doesn't show header column

Leooooooooo

I've been using QML TableView + HorizontalHeaderView with QAbstractTableModel as the model for a while now and wanted to implment filtering/sorting. So I've made a QSortFilterProxyModel and changed the model in QML to this proxy model.

When I do this the header column "HorizontalHeaderView" switches to using the data method instead of the headerData, and it switches to now using the rowCount method, so the header has multiple rows just like my tableview. Any ideas if I'm missing something I need to implment in the proxy model? I've tried adding the headerData in there without any luck as it seems it just doesn't call the method anymore with the proxy model set.

This is the HorizontalHeaderView that works without issues with my QAbstractTableModel model but not the proxy one.

Though the problem is fixed if I change the model to using "tableView.model.sourceModel" but this will cause issues I think down the line when I do sorting as the header won't be synced to the proxy model

    HorizontalHeaderView {
        id: horizontalHeader

        Layout.fillWidth: true
        syncView: tableView
        model: tableView.model
        boundsBehavior: tableView.boundsBehavior
        clip: tableView.clip
        resizableColumns: tableView.resizableColumns

        delegate: HorizontalHeaderViewDelegate {
            id: horizontalDelegate

            required property int index

            background: Rectangle {
                anchors.fill: horizontalDelegate
                color: Theme.color.primaryBackground
            }

            contentItem: BaseText {
                text: horizontalDelegate.model.display ?? null
                anchors.fill: horizontalDelegate
                horizontalAlignment: Text.AlignLeft
                leftPadding: Theme.spacing.small
                rightPadding: Theme.spacing.small
                font.weight: Theme.typography.weight.emphasized
            }

            Rectangle { // bottom border
                anchors.bottom: parent.bottom
                width: parent.width
                height: 2
                color: Theme.color.border
            }

            // Drag handler
            Rectangle {
                width: 20
                height: horizontalDelegate.height
                anchors.right: horizontalDelegate.right
                anchors.verticalCenter: horizontalDelegate.verticalCenter
                color: "transparent"

                DragHandler {
                    property real startWidth

                    onActiveChanged: {
                        if (active) {
                            startWidth = horizontalDelegate.width
                        }
                    }

                    onTranslationChanged: {
                        let newWidth = Math.max(tableView.minColumnWidths[horizontalDelegate.index], startWidth + translation.x)
                        tableView.columnWidths[horizontalDelegate.index] = newWidth

                        tableView.adjustLastColumn()
                        tableView.forceLayout()
                    }

                    target: null
                    xAxis.enabled: true
                    yAxis.enabled: false
                }

                HoverHandler {
                    cursorShape: Qt.SizeHorCursor
                }
            }
        }
    }