They’re all excellent. Is Garek the bad actor? O’Brian? The doctor? Kira? The security chief? Quark?
I claim you’re wrong/delusional if you want to critique the acting in ds9. It has some problems, but acting quality is the high point of Star Trek in ds9 - because at least there’s no Wesley crusher (and yes siskos kid is more compelling than Wesley!)
Jadzia I agree is marginally weaker than some of the others, but I do think that a permanent trill character was very good for story writing, plus eye candy, plus relationship with word was okay. At least she was a hell of a lot better than sad replacement character from the last season.
Come to think of it, the OP may have simply seen a few of the last season episodes which get pretty bad.
Then there's the queen of making you say, "I hate this character" Kai Wynn.