The catching position is a really, really good bet to be a dumpster fire at this time next off-season.
Were it me, I'd be desperate to add a young, cheap, offensively sound catcher to Stephenson-- or if I can get a really good one, in lieu of Stephenson.
But, IMO, it'll take signing or trading for someone outside of what they have currently in the system.
Duno's going to need PAs and innings. I suspect he repeats in Daytona. (116 total PAs and 180 innings total isn't much at all.) He might, at the halfway point, move up to Dayton if he's killing it, but he'll need a full season this year and next in the minors even if he's dominating. More likely, he's got three years before he sniffs PAs for the Reds. That's 2028. Stephenson will have been a FA a year before that, in 2027.