Coming from Duo, this sounds like a fake-empathetic remark for having done so poorly in this lesson. Passé composé is so hard for me!
French speakers: Is this a phrase that could be used to reassure someone in French or would it be considered non- empathetic and slightly rude? Please help...
Tone and manner, as well as context, would tell if this is empathetic or slightly rude. If someone tells you they tried something but failed, you can comfort them by saying "(au moins) vous avez essayé". As a question to someone complaining or blaming others, you may ask "(au moins) avez-vous essayé ?" and this would be (not rude) but authoritative or educational.
As is, the sentence here is quite neutral, since we don't know anything about the circumstances.
Does "Vous" count as plural in terms of the ending of "essayé", or is it context dependant?
With the auxiliary "avoir", the past participle is not to agree with the subject.