Try this:
<li dmx-hide="!getuserdata.data.query2.accountname" dmx-on:click="userlogout.load()"><i class="fas fa-sign-out-alt"></i> Sign Out</li>
And if you want to use the pointer as mentioned in my previous post then it would be like this:
<li class="hover-hand" dmx-hide="!getuserdata.data.query2.accountname" dmx-on:click="userlogout.load()"><i class="fas fa-sign-out-alt"></i> Sign Out</li>