Multiple functions updating datetime stamp in multiple cells

I am trying to update multiple cells based on input in each. The first works fine with a specific text from dropdown but I get no results on the other remaining 3. Here is the script I have:

function onEdit(e) {var sheet = e.source.getActiveSheet()if(sheet.getName() !== 'Dec2021' || e.range.columnStart !== 3 || e.range.rowStart < 0) return;e.range.offset(0,7).setValue(e.value == '2-Ready' ? new Date() : null)}

function onEdit(e) {var sheet = e.source.getActiveSheet()if(sheet.getName() !== 'Dec2021' || e.range.columnStart !== 8 || e.range.rowStart < 0) return;e.range.offset(0,9).setValue(typeof e.value == 'object' ? null : new Date())}

function onEdit(e) {var sheet = e.source.getActiveSheet()if(sheet.getName() !== 'Dec2021' || e.range.columnStart !== 7 || e.range.rowStart < 0) return;e.range.offset(0,9).setValue(typeof e.value == 'object' ? null : new Date())}

function onEdit(e) {var sheet = e.source.getActiveSheet()if(sheet.getName() !== 'Dec2021' || e.range.columnStart !== 6 || e.range.rowStart < 0) return;e.range.offset(0,9).setValue(typeof e.value == 'object' ? null : new Date())}