Pillar / furnace door is my go to for new mythic encounters until I figure them out and decide sth else might bring us an advantage. ToTT is a good trinket, in fact it is amazing to push some DPS, but it isn't as great for raw survivability as in example the pillar. stamina is jsut so good, especially if you don't know the fight well enough yet.
I only use ToTT in combination with BFD in order to push some DPS on encounters I don't need as much survivability, usually with HA + Sera like Flamebender Mythic in example. Burst spikes of > 100k DPS are pretty common then

but maybe if you name the Bosses that bother you? the mechanic that frags you, or just logs where you point out what exactly bothers you could help. (but maybe in an other subforum suited for it

)
also mind that it is still mythic, some Bosses will just hurt like hell. (kromog for example) here you just need to survive basically. that's it.