I have .setFormula() and stuck on this. I think the problem is the comma (&\",\"). I have researched several online forum before posting this q
You dont need single quotes ' around Sheet1.
Try
me.getRange('B8')
.setFormula('=arrayformula(concatenate(filter(Sheet1!E2:E,Sheet1!E2:E<>"") & ", "))"');
If you still need it, you need to escape it with backlashes like this \':
me.getRange('B8')
.setFormula('=arrayformula(concatenate(filter(\'Sheet1\'!E2:E,\'Sheet1\'!E2:E<>"") & ", "))"');
String § Escape notation