That is the thing, I play them regularly and I love multiplayer games like fighting, strategy, MOBAs, FPS games, etc. etc. In those I have almost no qualms or problems when loosing, but those are games where each match starts on equal terms.
In Hearthstone it feels like I have no real control of the situation. My randomly selected opponent draws random cards out of a random deck which all have random effects at times. If you have money you can probably edge your deck towards the winning side a bit by buying a couple hundred boosters, get the cards you need or be able to disenchant a few thousand cards you don't need to buy the specific cards you do want for that meta optimised deck.
It's not like a fighting game where you adapt your fighting style with a character depending on the opponents selection of a fighter, where you know "This character can do this and that, this is how I need to fight now to win". Here you are absolutely fucked if you haven't built your deck either with the most overpowered meta or don't have somehow extraordinary abilities of clairvoyance to know what you need to counter with your deck to have it ready before you click that search button. Unlike a fighting game I can't see what deck my opponent has selected, what cards he has, what I can do with my deck to counter his potentials, all I can do is play my cards and pray shit goes in my favour.
So you can tell me to "git gud" once I hear you "got gud" at a slot machine. Cause that is what playing this game feels like.
welcome to trading card games..
it sounds like you never played them. If you have a good deck, one that can adapt to what the opponent might send you, then the RNG odds are not really that relevant, because you will have something to answer the opponent.
This is no fighting game, a fighting game depends on how quickly you react with you buttons, it is action, here it is strategy, it doesn't matter if you don't press a single button until the last seconds of your turn, because as long as you think your best action to make the best trades, then you will win.
The difference here is that you are thinking about another different world in competitive games. In TCGs you only have your mind to win, and trust me, I played more than a month with only basic cards: if you think about your turns wisely, you will wreak havoc in the opponent, even if it has more legendaries than you and even when you don't win, you would have make at least a good match.
In TCG if you know what your opponent might be playing, you have a good edge. A common example: all mages run Flamestrikes, all good warriors run Fiery War(Win) Axe, all paladins run consecration, all priests run Northshire Cleric.
Examples like that.