Amazon Guide for Amazon Rainforest

Hello, apologies if this has been asked before. I'm going to be in Peru this coming May for a Machu Picchu trek, and was looking into going into the Amazon after. At this point in the trip, I'll be going solo and was having some trouble finding a tour that was friendly for solo travellers.

Does anyone have suggestions? Ideally, the tour would start in Cusco or another city in Peru. I'd also prefer a tour that's more physically intense, but it seems like most of them are on the comfortable lodging side.