Using lightning:workspaceAPI we can change Tab Label dynamically. Basically this component allows to access methods for programmatically controlling workspace tabs and subtabs in a Lightning console app. Here is an example to change Account record Tab Label “Account Name” to “Account Type” with “Account Name”.

Account Standard Tab Label:

Lightning Component:

<aura:component implements="flexipage:availableForAllPageTypes,flexipage:availableForRecordHome,force:hasRecordId" access="global">
    
    <!--Attributes-->
    <aura:attribute name="accFields" type="Account"/>
    
    <!--Component Start-->
    
    <!--Lightning Workspace API-->
    <lightning:workspaceAPI aura:id="workspace"/>
    
    <!--Lightning Force Data to get Account record-->
    <force:recordData aura:id="accRecordData"
                      layoutType="FULL"
                      recordId="{!v.recordId}"
                      targetFields="{!v.accFields}"
                      recordUpdated="{!c.handleRecordUpdate}"/>
    <!--Component End-->
</aura:component>

Lightning JS Controller:

({
    handleRecordUpdate: function(component, event, helper) {
        var accountFields = component.get("v.accFields");
        var workspaceAPI = component.find("workspace");
        workspaceAPI.getFocusedTabInfo().then(function(response) {
            var focusedTabId = response.tabId;
            workspaceAPI.setTabLabel({
                tabId: focusedTabId,
                label: accountFields.Type + ' - ' + accountFields.Name
            });
        })
    }
})

Add above created lightning component on Account Lightning Record Page.

Output: