Muun is fee siphoning attacking any sender to Muun wallet. There is a mandatory hop through a private channel with a fee of +1500ppm.
RoboSats will strictly not route a buyer payout for a net loss. Given that RoboSats trading fees are 0.2%, and it needs to cover the routing fees, RoboSats will never find a suitable route to a Muun wallet user.
Be careful, muun shills will call you mean...