You just need to move the form repeater code on the tbody:
<div class="container-fluid mt-2">
<div class="row">
<div class="col">
<form id="frm_addExp" is="dmx-serverconnect-form" method="post" action="/api/instProfile/staffProfile/teaching/addStaffModal/upd_staffExp" dmx-on:success="notifies1.success('Experience Info Saved')">
<div class="row">
<div class="col">
<div class="form-group mb-3">
<label for="inpSal_instStaffID" class="form-label">Inst Staff ID</label>
<input type="text" class="form-control" id="inpExp_instStaffID" name="instStaffID" aria-describedby="input2_help" placeholder="Enter Value" dmx-bind:value="frm_personalInfo.data.sv_inst_staff_id" readonly="true">
</div>
</div>
<div class="col">
<div class="form-group mb-3">
<label for="inpSal_instStaffID" class="form-label">Staff Type ID</label>
<input type="text" class="form-control" id="inpExp_staffTypeID" name="staffTypeID" aria-describedby="input2_help" placeholder="Enter Value" dmx-bind:value="frm_personalInfo.inp_staffTypeID.value" readonly="true">
</div>
</div>
</div>
<div class="row">
<label class="form-label"><b>Experience Details</b></label>
</div>
<div class="row">
<div class="col">
<div class="text-center table-responsive-lg">
<table class="table align-middle table-bordered border-dark-subtle table-hover table-sm">
<thead class="align-middle table-group-divider table-secondary text-center">
<tr>
<th scope="col">#</th>
<th scope="col">Experience Type</th>
<th scope="col">Organization Name</th>
<th scope="col">Designation</th>
<th scope="col">Job From</th>
<th scope="col">Job To</th>
<th scope="col">Add</th>
<th scope="col">Delete</th>
</tr>
</thead>
<tbody class="table-light table-group-divider align-middle text-center" is="dmx-form-repeat" id="formRepeat1" dmx-bind:items="1" min="1">
<tr>
<th scope="row">{{$index+1}}</th>
<td>
<div class="row">
<div class="col"><select id="selectExp_expType" class="form-select" name="expType">
<option value="">Select</option>
<option value="Teaching">Teaching</option>
<option value="Research">Research</option>
<option value="Industry">Industry</option>
</select></div>
</div>
</td>
<td>
<div class="row">
<div class="col"><input type="text" class="form-control" id="inpExp_orgName" name="orgName" aria-describedby="input2_help" placeholder="Enter Value"></div>
</div>
</td>
<td>
<div class="row">
<div class="col"><input class="form-control" id="inpExp_jobDesig" name="jobDesig" aria-describedby="input2_help" placeholder="Enter some text"></div>
</div>
</td>
<td>
<div class="row">
<div class="col"><input type="date" class="form-control" id="inp_jobFrom" name="jobFrom" aria-describedby="input2_help" placeholder="Enter some text"></div>
</div>
</td>
<td>
<div class="row">
<div class="col"><input type="date" class="form-control" id="inp_jobTo" name="jobTo" aria-describedby="input2_help" placeholder="Enter some text"></div>
</div>
</td>
<td>
<div class="row">
<div class="col"><button id="btn_addExp" class="btn ps-lg-2 pe-lg-2 btn-outline-success btn-sm w-100" dmx-on:click="formRepeat1.add()"><i class="fas fa-plus-circle fa-lg"></i></button></div>
</div>
</td>
<td>
<div class="row">
<div class="col"><button id="btn_delExp" class="btn btn-outline-danger ps-lg-2 pe-lg-2 btn-sm w-100" dmx-on:click="formRepeat1.remove($index)"><i class="fas fa-minus-circle fa-lg"></i></button></div>
</div>
</td>
</tr>
</tbody>
</table>
</div>
</div>
</div>
<div class="row">
<div class="col">
<button id="btn_saveExp" class="btn btn-primary" type="submit">Save Experience</button>
</div>
</div>
</form>
</div>
</div>
</div>