BaseTabBarController里面：

func setupVC(vc:BaseViewController,title:String? = nil){
        arrayShowVc.append(vc)
        let nav = BaseNavigationViewController(rootViewController: vc)
        nav.setNavigationBarHidden(true, animated: true)
        if isPad(),#available(iOS 18.0, *),let title = title {
            //图片用于 self.mode = .tabSidebar 时对应的展示
            let tab = UITab.init(title: title, image: UIImage(named: title + "_选中"), identifier: vc.className) { tab in
                return nav
            }
            tabs.append(tab)
        } else {
            addChild(nav)
        }
    }

BaseViewController里面：

override func viewWillAppear(_ animated: Bool) {
        super.viewWillAppear(animated)
        self.navigationController?.setNavigationBarHidden(true, animated: true)
        //这儿只做了隐藏跟显示
        if isPad(),#available(iOS 18.0, *) {
            if let children = navigationController?.children {
                self.tabBarController?.setTabBarHidden(children.count > 1, animated: true)
            } else{
                self.tabBarController?.setTabBarHidden(false, animated: true)
            }
        }
    }

备注：这只是我自己的处理方法。