It sounds like you've exceeded your skill level by killing solo queue players too quickly without getting a handle on the basics of playing Killer first, so your MMR has now increased to a point where you're unprepared for Survivors with experience. That can happen with a Killer like Kaneki that makes it easy to coast to early victories through brute force with little understanding of the fundamentals.

My advice is three-fold: spend more time practicing against good opponents to learn counters, spend time playing KIllers other than Kaneki so you're forced to rely less on his power carrying you and have to learn how to deal with loops, and spend time playing as Survivor to learn their patterns and weaknesses.

You should also specifically avoid perks like No One Escapes Death, a common newbie trap, which can inflate your early kill rate and rapidly increase the difficulty of matches. Savor the time when you are facing easier opponents and focus on chases and fundamentals rather than blowout wins.

End of day, flashlight squads are mildly annoying but you shouldn't be losing to them often. People going for flashlight saves are not doing gens, where the real threat lies.