Esto me hace mas feliz que probablemente debe
This makes me more happy than it probably should
Yeah, you can. Like this, though:
"Esto me hace más feliz de lo que probablemente debiera/debiese/debería/debe"
with alternative verbal tenses in decreasing order of natural-soundingness [that
debiera is fossilized].
Other example of dangling modals that are not so readily translatable:
"His work is better than yours ever will."
Su trabajo es mejor de lo que el tuyo lo será jamás. [uses 'ser' again]
"He works better than you ever will."
Trabaja mejor de lo que tú lo harás jamás. [dummy 'hacer']
"She cooks like you never will."
Cocina como tú nunca lo harás [dummy 'hacer' again]
For most other auxiliaries you can use the corresponding tense of hacer: did -
hiciste, would -
harías, ... but
deber has its own personality and so you can actually leave it like that.