2017 jeep wrangler unlimited Sahara automatic oil everywhere and air filter full of oil

that's their problem now, hope you have your receipts.

At least you have a warranty. If there was any oil related engine damage you have a good case for a new engine.

What kind of damage can it cause ?

leaving the oil cap off was bad- if the engine runs out of oil it blows up- BUT you drove 3000 miles and the engine was still running and I guess no oil warning light came on- SO maybe the cap was just left loose, or slightly ajar or something like that- if you are worried about oil getting into the combustion chambers, it most likely is harmless for the engine to burn an oil/gas mixture, within reason, maybe just some fouled plugs- and your engine did not run out of oil completely so maybe your engine is ok- let's hope so- such a shame, on a 2017 that maybe your engine experienced more wear than it needed to- now you are just stuck- factory warranty will not cover human damage even tho it was done at one of their dealers- and the dealer will probably try to deny any responsibility because they don't want to be on the hook for a new engine- even if you got a new engine put in, if their mechanics can't do an oil change I wouldn't trust them to do an engine swap- best case scenario: your engine was not damaged, the dealer will accept responsibility, give you a courtesy car and take the time to clean the engine, the engine compartment, change all filters, and compression test the engine to make sure it was not damaged- at no cost to you- worst case scenario: oh, let's not go there, it would involve lawyers-

The cap was completely off they found it laying on the black metal part of my jeep. The mechanic that did the oil change at the dealership quit his job on Friday. The dealership agreed it was their fault. They cleaned it for an hour today and replaced the air filter and did another oil change. They told me to come back every 30 days for the next 6 months and in the spring they are doing a full engine detail. I will ask them for a compression test. I'm so sad. I had less than 6000 miles on it before the road trip and their stupid mistake