angular Ts中使用echarts节点重合问题

在angular项目中使用echarts画了一个流程图，如图

六边形和序号为两个重合的节点，光标悬浮的时候，六边形节点的层级会自动提高导致覆盖序号节点，如图

代码中并没有设置光标悬浮，并且尝试一些查到的改变层级zlevel,z等都无效，怎样才能让序号节点始终在最上面，或者怎样可以设置节点光标悬浮时无任何动作。

angular版本为11.2.0，echarts一开始为4.4.0，现升级为5.4.1 均无效

部分代码如下：

  
class="echart" echarts (chartInit)="chartInit($event)" #Histogram [options]="options">div>

nodes = [
      { 
        id:'t1',name: '11', value: [100, 1950],content:'hahhahahah',
        symbolSize: [200, 80],
        itemStyle:{color:'blue',borderColor: 'blue',},label:{color:'#fff'} 
      },
      { id:'t2', name: '22', value: [450, 1950],symbolSize: [300, 60]},
      { id:'t3',name: '33', value: [830, 1950],symbolSize: [300, 60],},
      { id:'t4',name: '44', value: [782, 650],symbolSize: [400, 60],},
      { id:'t5',name: this.nodeTitle.t4, value: [410, 650],symbolSize: [300, 60],},
      { id:'t6',name: '55', value: [80, 650],itemStyle:{color:'#C00000',borderColor: '#C00000',},label:{color:'#fff'},symbolSize: [300, 60],},

      { name: '1', value: [380, 1950],symbol:'circle',symbolSize: [30, 30],itemStyle:{color:'#D7091D'},label:{color:'#fff'}},
      { name: '2', value: [740, 1950],symbol:'circle',symbolSize: [30, 30],itemStyle:{color:'#F76F20'},label:{color:'#fff'}},
      { name: '3', value: [652, 650],symbol:'circle',symbolSize: [30, 30],itemStyle:{color:'#FFAF00'},label:{color:'#fff'}},
      { name: '4', value: [320, 650],symbol:'circle',symbolSize: [30, 30],itemStyle:{color:'#57BC7F'},label:{color:'#fff'}},
      { name: '5', value: [-10, 650],symbol:'circle',symbolSize: [30, 30],itemStyle:{color:'#2DBBCE'},label:{color:'#fff'}},
]
options = {
    tooltip:{
      show:false,
      trigger: 'none'
    },
    backgroundColor: "#f4f4f4",
    xAxis: {
          min: 0,
          max: 1000,
          show: false,
          type: 'value'
        },
        yAxis: {
          min: 0,
          max: 2000,
          show: false,
          type: 'value'
        },
    series: [
      {
        type: 'graph',
        coordinateSystem: "cartesian2d",
        layout: 'force',
        symbol:'path://M319.0784 0h2750.498133a102.4 102.4 0 0 1 89.9072 53.4016l226.7648 416.0512a102.4 102.4 0 0 1-0.580266 99.072L3159.722667 971.656533A102.4 102.4 0 0 1 3070.395733 1024H318.907733a102.4 102.4 0 0 1-91.562666-56.541867L22.869333 559.3088a102.4 102.4 0 0 1-0.1024-91.477333l204.629334-411.067734A102.4 102.4 0 0 1 319.044267 0z',
        data: this.nodes,
        links: this.links,
        itemStyle: {
          normal:{
          color: "#fff",
          borderColor: '#454545',
          borderWidth: 1,
        }
        },
        lineStyle: {
          normal: {
            width: 2,
            color: '#454545',
            // curveness: 0,
          }
        },
        label: {
          show: true,
          color: '#333',
          fontSize:'20',
          fontWeight:'600',
        },
      },
    ]
  }