You need to allow him a move every 3 moves. You can take the damage of a tick tock well, if you are stocked up on Free Will on overdrive.
Equip 3x Free Will (4/4), 2x Traumatize (2/2), 1 Dark Infusion, 1 Terrify (2/4 or higher). Now one slot is free: I like implosion to make his deep burning burn even deeper. If you happen to have insecurity or dark echoes, you can use those instead.
The first part of the fight is simple: You traumatize him once, then distribute free will / terrify to heal & shield for two moves. You can set Veradux to passive and leave Roald neutral, so he can use his shield, too. Be sure to counter tick tocks with free will, and dispell his echoed screams. You hit the Baron with your damage amplifier, when he burns himself.
When he changes his strategy later, counter his epiphanies and dispell his confinements (or shield them). Make sure you all are healthy enough to survive a nightmare attack - then use its healing buff to your advantage.
Actually, it's easier than this reads.