I don't understand the benefits of using Manjaro over Endeavour OS. I have not heard anything good about that Manjaro only how badly they treat contributors, maybe it's just my echo-chamber but that's the impression.
Endeavour OS had some turbulence recently with their devs, but in terms of pros, i don't think there is much difference, personally Manjaro seems to have more support, so if you get stuck, your chances of help may be better
Manjaro is more well known, but so are it's practises.... EndevourOS will get it's well earned moment to start shining in the light very soon I believe.