How to get my dogs to play nice

Hello friends, my girlfriend and I got a 6 year old beagle mix (Max) rescue about a year ago and he had bad anxiety. We recently got a 6 year old Husky mix (Echo) for a companion for his anxiety and it has really worked to calm him down when we are not home. Max has always been good around dogs and has not been aggressive but seems to have never learned how to play. Echo tries to play with max and Max plays for a bit, but seems to get nervous and either growls and snaps or tries to hump which makes echo mad. It has only gotten bad once where I had to step in. Max takes trazodone when we are gone to keep him calm but I am worried about it escalating when I’m not home. we have a camera and they sleep all day when we are gone and have plenty of cognitive toys. Max is also food aggressive and we keep them separate when they eat. Echo seems to know boundaries and backs off when Max is protective over toys. How do I teach them to play nice and respect boundaries?