Hmm… Maybe you just need to finally grow up? 
And there I was, grumbling about those big babies in their twenties, running around in dirty white socks and so on… Never mind that, though, to the issue at hand…
Yes, many have observed a lot of such ‘strange’, if not outright suspicious, phenomena (e.g.: Rigging: Win condition drawing - #2 by SparkyElf-2852 and all those seemingly countless further links). Forum ‘paladins’ will keep telling you that the game is not rigged, but that’s not the point. What is, as you have aptly put it yourself, and I should praise you for it, is your reaction to it all.
Whether the game is rigged like a casino or just frustrating — more on that later — the question is: what are you looking for in it, why do you keep playing and repeating the same unpleasant experience? Are you truly having fun or just trapped in that emotional roller-coaster, akin to an addiction of sorts, like some poor guy who keeps losing in a casino, clinging to a false hope that the tables would be turned somehow? PS Come to think of it, there’s also the thrill of anticipation and so on… Some people here would tell you about ‘dopamine hits’, but personally, I’d refrain from such simplistic theories.
As for the game design, in my view — make no mistake, the game is designed to hook you on it and keep you playing, moreover, the cycle of hope, hype and disappointment seems to be pivotal to the game model — it probably is supposed to be frustrating and keep you in that miserable state (see above re ‘roller-coaster’, ‘cycle’ etc), where you’re thinking that you’re having fun and playing the game, while the game is playing you, as I often put it, instead.
I suppose you could ask yourself: is this really your cup of tea? From you post, sounds like it’s not. Of course, you’re your own man, I’m just writing down my thoughts about your situation, as you have requested.
You’ve mentioned the competitive aspect:
Is that what you’re after, what motivates you? Then why not play something more skill-intensive instead, as opposed to HS, which is admittedly very much like a roulette, with a lot of ‘RNG’ and ‘exciting’ 
stuff (just like you said, all those crazy swings, sudden generation of game-changers etc) in it?
That’s actually a very reasonable and mature piece of introspection, if you ask me. I think you might have answered your own question partially, but I have elaborated on it above.
Is that a question?
No matter, I think we’ve covered that part.
I wish you… maybe not even ‘good luck’, no, but making an informed choice, a decision of your own, and having fun — truly and as a result of it.