I don't think there's anything certain about Galvis. He's still a free agent. They could do better, they could do worse. I'm not even certain Maton would be a downgrade from him (or Torreyes), though obviously just for the bench spot, not significant playing time.
Didi should play quite a bit of DH too if his bat comes back/he's healthy. But bringing back MIller or someone like him is also a good answer there. Last years bench was always kind of short one bat (it was Miller and no one) so they just need to address that to also add someone to the DH pool.