[SalesForce] Dynamic row actions in Data table using LWC

On your datatable's data function callback (assuming you're getting the data you need from apex) you can set the return type's properties dynamically and use those properties for setting the column properties. This could be color, icon, name and other attributes for the column.

If I understood correctly you can create a new column if the requirement is met and display it on a column every row. This is aura but it should be the same in LWC.

JS Controller

var resultData = response.getReturnValue();
            if (resultData !== null) {
                resultData.forEach(function (record) {
                    if (typeof record.Id != 'undefined') {
                        if (record.IsActive) {
                            record.displayIconName = 'utility:check';
                            record.showClass = 'greencolor'
                        } else {
                            record.displayIconName = 'utility:close';
                            record.displayIconName = 'redcolor';
                        }
                    }
                });`

Column

            { 
                label: 'Active',
                fieldName: 'IsActive',
                type: 'text',
                sortable: false,
                editable: false,
                "cellAttributes": {
                    "iconName": {
                        "fieldName": "displayIconName"
                    }, "class": {
                        "fieldName": "showClass"
                    },
                },
                "fixedWidth": 100
            },

We would normally have property name in type attributes based on which you can differentiate. However you can also use label (if they are different - usually they are same) or any other attribute in event.detail.action.

Below is example: (Playground Link):

columns = [
    { type: 'button', typeAttributes: { label: 'First Button', name: 'first_button', variant: 'base' } },
    { label: 'Name', fieldName: 'name' },
    { type: 'button', typeAttributes: { label: 'Second Button', name: 'second_button', variant: 'base' } },
    { label: 'Phone', fieldName: 'phone', type: 'phone' },
];

handleRowAction(event) {
    console.log(JSON.stringify(event.detail.action));
    if(event.detail.action.name==='first_button') {
        console.log('clicked FIRST button');
    } else if (event.detail.action.name==='second_button') {
        console.log('clicked SECOND button');
    }
}