You can still get the mount in Shadowlands, similar to Karazhan Nightbane mount
You can steamroll this with a tank and four DPS pretty easily, there's not enough damage that will go out that will trouble you honestly.On the last boss himself, you *can* reset the boss, pull him again after that, push the button just before phase 2, and then pop BL+CD's, and you won't actually have to ever deal with the input sequence.
Sadly no friend of mine wants to do the no-death run with me :(It almost happened once, but we squished ourselves with miniaturizer lol
you can just kill the last boss and reset the instance and try again
1. reset the boss by dragging it outside the room. (be fast as the door closes quickly)2. engage the boss the moment it re-spawns with aoe's on ground etc. (this prevents the button for Hardmode from despawn on engage of the boss)3. get the boss to 10%4. have 1 player press the HM button,5. kill boss, loot mount, its worked since day 1 and still works. your welcome(the reason this works is because the button to do HardMode will despawn if you attack the boss, the thing is, when you reset the boss, the main boss spawns in 0.5seconds before the acutaul hardmode button, so if your quick enough, it cant despawn the hardmode button if it hasnt re-spawned in yet to begin with.