@AymCTL
So I must be one of the lucky ones to basically never have had to deal with hit reg issues. I have been playing one Mnk PC since the game came out and can say that I have not really been affected by this outside a handful of times.
The times that I had been affected were when I had internet issues like lag, high ping etc. and a bit before I got my new PC.
I wish I was as knowledgeable about Apex a you suggest. There are others here with a bit more knowledge than me @hayhor @E9ine_AC @OldTreeCreeper and our lovely Apex CM extraordinaire @EA_Mari to name a few.
I will say this though I do notice that when I play with my two close friends three stacking and we are in a grove damage output, kills and winning games increase. This is also the case when I get decent randoms to play with. When I get matched up with bad players, Hot drop Harry, Rambo, Rage quitters, and or complete noobs it affects my games negatively. This has however nothing to do with hit reg.
As far as cheaters go I do not see many of them anymore since I stay away from ranked play the first week of a split and the last week as well. I also do not play LTM's as much as I used to because they seem top be a magnet for cheaters and or super cracked players chasing shiny badges and the MM is pretty shady then. Same goes for TDM, Control and Gun Run, to many quitters cracked players and or cheaters I only use those modes to play 2-3 matches to warm up for Trio Pubs.
Just because your internet connection seems and feels fine does not mean it is. I use O2 and it could be just fine however the main trunk lines are owned by Telekom and they sometimes have issues that can affect me. With that in mind asking my ISP and they will say all is fine on there end but that Telkom is having issues and they can do nothing about it. I had no internet or phone for 3 days and O2 had to tell me that it will be back up once Telekom got there ...... together and fixed there own issue. So occasionally I will get a 1-2 game lag issue even though my internet is fine.
I could not say if there is an input issue that could be affecting you when you use controller on PC or if AA is affecting you since I have never ever used a roller on my PC. Strictly MnK player that I am.
I hope things get better for you in game.
I especially hope things get better IRL for you as well. Family comes first, so spend the time you have with them. I wish you and yours the best.
If you need some one to talk to, do it, friends, family, a coach can be good ways to do so.
Here in the community if you need anything you can DM me and I will help the best I can, even if it is just to be a good listener.