I agree with everyone's sentiment here about Smurfs and cheaters. It is crazy out of hand. They need to require a specific number of days before an account can be invited and download Deadlock. I suggest 3+ days old accounts in order to receive an invite and download the game. Match making should also take into account the number of hours a player has in the game (in-match hours only). Moreover, or optionally steam accounts should require a real phone number when setup and a phone number can only be attached to a single steam account. With exceptions for family, children and lost (requiring new) accounts. There would need to be a process for those.
Side note, from a general internet user and gamer. The day is coming where we will be required to present a real ID or some form of ID to play games on steam and/or use the net. All politics aside, it is an unfortunate truth to the progress we are seeing in the digital world lately.
Overall, this wouldn't just solve Smurfs and cheaters in Deadlock. It would solve it in nearly all online PVP/PVE games. Do I enjoy that idea? No. Do I want it to happen? No, more often than not. Will it happen in the future? Yes, at some point soon-next 5-8 years realistically. With AI advancements and everything else they will have too or the 'dead internet theory' will become the 'dead game theory' with just bots playing bots to sell accounts to real people who just play with other bots until the game dies.
*EDIT* With some sort of ID attached to (any type) of account it would allow companies to not only ban specific people from playing their game, unless they use someone else's ID. It would allow them to go after the network on people who create, support, and manage cheats.