The way matching making works- getting the same matchup that you've been struggling with.
So, a lot of people have made this claim, but in my view this is confirmation bias. My own experience is anecdotal, but in the literally hundreds of hours I have played, and thousands of matches, I haven't seen any real evidence to back this up.
There are lots of decks that people have, and there are thousands of combinations of cards. So firstly, you likely aren't get matched against literally "the same" deck in succession, though I concede (and what you likely mean) you may very well come up back to back against a Hog/Inferno based deck, or a Bowler/Graveyard deck, or a Golem/Tombstone deck. And there always be that deck that you struggle against because every deck is weak to some other combination (though if you are truly struggling with more than one "core" deck you are going up against, then you may have to consider changing your deck and/or strategy).
The thing is, the core of such decks are common enough that it isn't statistically unrealistic to come up against a Hog/Inferno deck 2 or 3 times in a row. You just tend to remember those times that you do because its frustrating. Not to mention if you are feeling defeatist about going up against a particular deck then the second or third time you come up against it in a row you can start playing irrationally. I have that myself, and need to check myself from playing too aggressively which tends to only increase my chance of losing to a deck I'm weak against. Putting the game down for a bit and coming back to it later is a great way of breaking a losing streak.
If you really think the game is working against you in the matchmaking, I'd suggest going through your activity log which will have your last 20 matches there, and count the number of times you have actually been matched against your "nemesis". My guess is that it isn't coming up as much as you imagine.
And again, Supercell has no need to "cheat" anybody on the ladder. The game unlocking and leveling structure is so well balanced that any player will naturally hit the wall and be required to either grind or pay because players above you have cards at higher levels or cards you don't have or have no counter to. And you'll have to do that multiple times as you ascend through the arenas.
The way enemies get targeted before other enemies, the way hogs will redirect themselves back to the tower for no reason,
This honestly sounds like you might be on a laggy connection if things are not targeting consistently or are otherwise erratic (the hog redirect especially sounds like the simulation on your side needed to be "corrected" after placing a building against a hog "too late" which itself would happen a lot on a laggy connection).
Something that is not immediately obvious though, and which might be contributing to your issue, is the unit graphics are misleading, especially for flying units. Where the units actually are on the map is where the shadow of that unit is, and that is what the targeting is based on. For example, this can make targeting a Balloon unit next to a tank incredibly frustrating until you start looking at their shadows (even then, it requires a lot of skill sometimes).
The way an enemy will survive with just a sliver of heath so they can deal damage behind a tank. It doesn't feel random.
It isn't random, and it isn't supposed to be. This is by specific design. The damage that units do and the health they have is not variable, but static every time. And the interactions between cards and particularly between cards of different levels have been carefully balanced.
This is not cheating.
You need to pay attention to what units you are putting up against other units, and particularly the levels of each. An example of this is the Fireball. A level 9 Fireball will cause 689 troop damage. A level 8 Muskateer has 656 health, while a level 9 Muskateer has 720. A good use of a level 9 Fireball might be to hit a level 9 Muskateer passes the tower, eliminating the unit entirely while getting some damage on the tower too for an even elixir trade. However, it's not such a great decision against a level 9 Muskateer given it will be left alive, and you'll have to spend more elixir to kill it not to mention something else tanky will probably be dropped in front of it. In the latter instance, it is better to wait to see what else is dropped in support and to react to the combination of those units.
So, yes, sometimes units will survive with a sliver of health and go on to wreak havoc. That's an integral part of the higher end game. You need to be skilled to make sure this doesn't happen, and that means paying attention to the levels of units, knowing the levels of your units off by heart, and learning the interactions between the cards with level parity and level disparity.
Hope this helps.