Why not pay for a carry? (Pinnacle Bosses)

After getting the best gear I could and slamming 15s I decided I wanted to try pinnacle bosses (Blind, my mistake?). I liked Breaches so I picked Xesht, after a bit of grinding (getting 8-10 shards per breach) I had 200 shards and ended up just buying the rest from currency exchange. Super excited I start clearing trash and get to the boss, at this point im focused up and doing a decent job of sight reading what he does and then I get one shot. Ok my bad.. I guess I'll watch a guide, Round 2 against Xesht, doing a bit better, one shot.

Now Im down 2 Breach stones and being slightly psychic I witness a future of me dumping 10 more stones and probably getting the kill. So instead I bought 4 stones and got someone to carry me.

This feels extremely bad, I was hyped for the content and now I dont have to interact with it ever again purely because the time invested to grind currency and stones to get better is a thousand times harder than just having some juiced up mage or something kill the boss. I would like to see a practice mode put in, it could cost something like 10 shards or some gold or whatever and drop no loot, even have it so you have to have at least one boss kill to practice it.

I dont want to have to watch outside guides or pay people to play the game, just give me a way to get good.