I know the movies aren’t exactly canon, but they did show part of what happened when Sauron had the ring. Through a combination of armies of different races, he and his hoards were defeated when Isildur chopped off his hand (hand in the books, fingers in the movie?)? His essence was scattered and he could no longer maintain corporeal form, but through his power was still able to maintain his status has head cheese of Mordor
Under these restrictions, he was still able to influence others, control the Ringwraiths, and amass an army that almost defeated the free men of Middle Earth. So had he gotten the ring back, would he have been able to just control people’s minds? Throw fireballs from a hundred miles away? I mean, his last physical battle was lost from a lucky slice of a hand that had the ring. What’s to say that if he got the ring again, they couldn’t just do that again?
What I’m getting at is that with the One Ring, his power supposedly would be magnified, but he’d have a physical target of a humanoid form that can be attacked. That seems much more vulnerable than a floating eye on top of a tower in the middle of Mordor surrounded by thousands of orcs. Couldn’t they give him the ring, wait for him to stroll onto the battlefield, and shoot an arrow into his eye or something?