Dragapult @ Heavy-Duty Boots - So that you dont take unnecessary hazards damage, including toxic spikes.
Ability: Infiltrator  
EVs: 252 Atk / 4 Def / 252 Spe  
Adamant Nature  
- Dragon Dance - Goated set up move.
- Psychic Fangs - At +1 Dynamax, it should kill a toxapex.
- Phantom Force - Stab move, does massive damage and wins games if you spam this at +2 att dynamax. 
- Steel Wing - To be able to take on fairies such as clefable or hatterene, I have this here over dragon claw because if a ditto comes in it can kill your dragapult with ease by using dragon claw. With steel wing they aren't able to ohko you. You're most likely going to make them panic and press a fast phantom force.

There are ways to beat people that use ditto correctly. If you're good you'll will Dmax phantom force the ditto. By doing this you're able to scout whether they will click steel wing / psychic fangs or are stupid enough to phantom force. From there you should be able to clean up 2 - 3 mons or outright win the game if you are given the chance to set up. If you do face a ditto though, I would try to force them to dmax before you send out your dragapult otherwise dmax ditto can be a bit of an issue.

This set is cool because you can generally turn most walls into set up fodder and if they somehow do too much damage to you, you can easily dynamax and have 600 + health whilst being able to ohko most threats and walls. You may look at this and regurgitate thinking of how bad this probably is because you didn't make it and that I haven't provided any replays, but yes. Yes it is viable. Yes it is good. Yes it can be annoying to build around.