It is clearly a new everyday position but he's improved as the year progressed (he did play a handful of games at the hot corner at High-A Wisconsin in 2022 if I'm not mistaken). He definitely has the arm for it. At present, however, the thing that has plagued him at both 2B and 3B is he is just a little bit stiff. I don't know how to describe it as anything other than that. He has made some surprising plays, from time to time, as well - a charging barehanded play in the past several weeks comes to mind. Whereas, earlier in the season, I was like: "Oh boy, this is a big project." I've seen enough progress at the hot corner to understand why they keep giving him shots there. Well, until they shifted him to 1B this past week - which, as Daniel point out in a recent GT, might be an audition for an interested ball club (I sure hope not, his work at the plate is so advanced - the Brewers could absolutely use his bat in the lineup every single day).
Anywho, this is a long winded way of saying: He's made progress. BUT, is it enough? I don't know. He has a season FPCT of 0.921. This isn't very good. He only has 11 errors in 592 2/3 innings - which is quite palatable all things considered. But the range and the ability to make those range plays - plays MLB caliber 3B need to make is very much in question.
The question remains: Are they trying him out at 1B now because, organizationally, they understand they have a major lack of depth there and Black's bat plays anywhere? OR, is it for some other reason? Time will tell.