Depends whether you’re playing Turbo or Ranked. For instance if we’re playing ranked where everybody is of similar MMR then yeah, massive KDA difference over a number of matches would be suspicious and you could weed out the smurf.
However, if you’re playing Turbo, the matchmaker gives zero fucks about who it puts on your team or who it puts on the enemy team. You could get 3 divines and 2 legends queuing on one side and the matchmaker puts them against 3 guardians and 2 archons. It’s pretty messed up. So you’d often get massive KDA differences in that game mode.
Go no lower than an intel i5 or AMD ryzen 5 for the CPU. Make sure the laptop has a dedicated GPU too. Get one with 16GB RAM and an SSD. Anything less and you’ll run into a lousy low frame rate experience.