The couplings run against each other
Potency and selectivity are linked because related proteins have similar pockets; the features that improve fit in one often improve fit in another. Potency and metabolic stability are linked because the greasy groups that strengthen binding also tend to attract liver enzymes. Safety is linked to both, because binding-improving groups can also react with unintended targets.
What is actually being optimized
Not the maximum on any single property, but a profile that is acceptable on all of them. A moderately potent, selective, stable, non-toxic compound is a better candidate than a superb binder that fails on everything else.
AI does not remove the trade-off. It predicts the full profile across many candidate structures at once, so the trade-offs become visible and can be navigated before compounds are synthesized.