I will advise against M:C. Both DT and M:C are designed to be rhythmical boxes with melodic stuff as a bonus. You can run M:C as a sound module but in this role it’s rather limited. Check my and @bibenu replies in this thread.
As a DT user myself I would suggest you to look for a poly synth with a keyboard first. This way you will not only cover melodic part but also will have useful interface for entering notes into DT: used Minilogues, Microkorgs, Mininovas. Microfreak as well even though it’s paraphonic.
If you are ok with DT’s own keyboard layout search for polyphonic modules like already mentioned Micromonsta or Blofeld.
Then monophonic synths with a keyboard. After them monophonic modules and only then a groove box like MC.