Hello all, I have a problem that's stumping me.

We own a home in a neighborhood with smaller lots, and the back of ours has old chain link (verified ours) right at the property line. On that side, the neighbor’s property slopes up immediately at the fence, and in about 30 short feet, their house sits above ours. This part of their property is a pain in the butt to maintain due to the slope, so the owners told us they just don’t. Therefore, we have two feet of leaves stacked up against our fence with trash embedded in various spots. Small trees have sprouted and grown around the fence. 1/3 of the fence is completely engulfed by vines that have grown on their side, and I spend my summers cutting them back from our side. Additionally, our backyard has a view of the back of their shed at the end of their driveway, which is where they keep their trash cans, recycling, propane tanks, etc. Understandable—it’s where I’d keep ours. But that, coupled with the leaves, tree sprouts, and trash, and the slope is where they let their dog poop… it’s gotten to be too much. It's now a rental, and the stuff behind the shed has built up to include an old mattress, broken furniture, machinery, etc., and the attempts the owners used to make to at least somewhat maintain the slope aren't happening anymore. Also, I’d love to create a backyard space with a little privacy. I don’t expect my neighbors to change anything; it’s their yard and they have the right to do what they want. But I’d like to create some sort of barrier between us and that slope, and I just don’t know how. In this area, it would be ridiculous to invest tens of thousands in a solution, although I don’t want rolls of bamboo fencing attached to the existing fence, either. The only idea I have is to build a stone wall up about two feet to contain the leaves, and then a 6’ stockade on top of it. We’d still be able to see the shed, but it could contain the site of the slope and hopefully the poop smell. I’d just do an 8’ stockade but I think the leaf buildup would ruin the bottom too quickly. These are also very expensive options. And then how do we handle what’s built up on their side? If we rip up the chain link, we’d have to clean up the leaves, trash, and trees/plants just to get a new fence in. The trees are mostly small but two are about 6’ and well-established. We’d be tackling roots and essentially digging up our neighbor’s property. I suppose another option would be installing a new fence alongside the old one and then taking the old one down so we don’t have to disturb much, but again, we’d then be on their property. I know I’ll have to write the owners. But is there an option I’m missing? Is there a better fence solution that anyone can think of? Arborvitaes are out as we have a large maple back there, and we wouldn’t be able to plant anything around that due to the roots (and they wouldn’t get sunlight). Thanks for any insight!