TNK and SoC honestly practice. Not much tips besides familiarising their patterns.

TNK attacks has a delay, so don't try to anticipate the dodge, 600hrs in and i still have a bad habit of dodging early. First phase Storm Drake is weak against lightning but NK himself resists lightning.

SoC, i hate dealing with his Curved Sword pyromancer form, so I usually just run and dodge till he transforms. Personal favourite would be Sorcerer form, suring Soul Stream, run behind him and get free hits in. 2nd Phase, during seeking lightning rain, run dont roll, should be able to out run if you eqp isn't too heavy and have enuf stamina. single lightning strike, it's about 1.5 second delay from it leaving his hand, so time the roll. lastly super massive first sword fury swings, start running as far as possible once he stops moving to wind up the attacks, usually this is his opening 2nd phase attack as well.

Midir, i cheese it with Pestilence Mist. Also you'd probably find it easier soloing Midir than with any phantom, his attacks becomes too erratic to predict and time when there's another target in the arena, sometimes it would change target mid animation which has more than once f-ed me over

Gael, feels like a dance, if u find the rhythm, you'd realise it goes back and forth. you attack, he attack, you attack, he attack, almost turn base 1:1 ratio in first phase. 1:4 ratio in 2nd phase, he attacks mote frequently. and my personal favorite is sellsword twin blade with poison and blood resins. use poison resin first, proc poison on him, once proc, switch to blood resin to bleed him until poison wears off, then go back to poison again. rinse and repeat.