Boost the hazards of the jungle. Make DCs tougher and more frequent for things like exhaustion, and add additional penalties for dehydration and overall exposure to jungle rot (penalties like CON penalties, disadvantage, diseases, etc). A high level party will most likely have access to spells to mitigate all of this, but it still forces the players to choose to spend valuable slots to constantly keep up with the jungle.
Make speed a priority. Make random encounters frequent. These two things will prevent the party from taking rests whenever they want, recharging their spells. Combined with the above, and the decision on when and how to use spells to overcome the jungle become more important.
As far as monsters, I’d use lots of swarming monsters. Swarms of insects, snakes, undead, and large packs of dinosaurs. With bounded accuracy, swarms can still make life tough on higher level PCs. I’d also make sure all important monsters had legendary actions and minions at the ready. Have a few monsters with access to counter spell. That always ruins a PCs day