JSFiddle - React, Tailwind, and code Playground

HTML

<table><tbody><tr><td width="64">8"</td><td width="64">6"</td><td width="64">5"</td><td width="64">4"</td><td width="64">3"</td><td width="74">2"</td><td width="100">inch</td></tr><tr><td rowspan="2">76</td><td rowspan="2">69</td><td rowspan="2">48</td><td rowspan="2">27</td><td rowspan="2">20</td><td rowspan="2">11</td><td rowspan="2" width="100">A</td></tr></tbody></table>
<br>
<table><tbody><tr><td rowspan="2" width="110">Status</td><td width="110">time</td><td width="110">power</td><td rowspan="2" width="110">second status</td><td width="110">D</td></tr><tr><td>Time</td><td>( bar )</td><td>D1 </td></tr><tr><td>A</td><td>1</td><td>32</td><td>(B)</td><td>25</td></tr></tbody></table>

JavaScript

document.querySelectorAll("table").forEach(table => {
	let tr = table.getElementsByTagName("tr")[0];
  let tds = tr.getElementsByTagName("td");
  let selectorStr ="tbody tr:nth-child(1)"
  
  let maxRowspan = 1;
  
  for (let i = 0; i < tds.length; i++) {
  	if(maxRowspan < tds[i].rowSpan)
    {
    	maxRowspan = tds[i].rowSpan
      selectorStr += " , tbody tr:nth-child(" + maxRowspan + ")"
    }
  }
  
  console.log("Max RSp: " + maxRowspan);
  
  var nodes = table.querySelectorAll(selectorStr)
  
  for (let i = 0; i < nodes.length; i++) {
    nodes[i].style.background = "#1DA600";
  }
});