Concrete – How to flatten out a small, localized bump on a concrete subfloor

If you are on slab, the planton (or DeltaFL) should be a good option.

As I commented in that answer, I re-did my basement a couple years ago and used DeltaFL, and it's been great. It really does feel like a regular above-grade floor, and isn't cold at all. It's reasonably cheap to install, my cost (for the membrane and plywood) worked out to about $0.83/sqft, so at that price it would cost you $830 (plus some tapcons, tape, etc). This only gets you to a subfloor, so then of course you need to add on the finished floors.

If you're not on slab, and there is an unheated crawlspace or basement below you, and your floor is a wood floor, the best option is to insulate from underneath (something presumably your landlord should be doing).

Perhaps you're thinking about this in the wrong order.

What if you applied the plywood to the almost level sleepers and then leveled a surface over the ply?

I think you''re going to have a very difficult time leveling sleepers as you have in that photo.

EDIT: Per your comment that you intend to install tile atop ditra.... you have a very forgiving tolerance with the subfloor, then! Glue and screw the ply into the sleepers. Then apply the Ditra. You can level out imperfections in the leveling with thinset below the tile depending on just how bad things are.