It's possible that I just have a different view of modern NBA basketball. I think you can get quite far with multiple guys who are elite scorers and middling passers, and then find guys to fill in around them. Kawhi-led teams are a good template here, and if I squinted I could see Tatum/Brown in that mold (I can't quite go that far, because I think Tatum is an underrated passer whose assists are low for structural reasons).
The basic theory is that what you lose in passing, you make up in constantly compromising the defense. If you have shooters/playmakers around that in the DWhite mold (or even in the mold of roleplayers GSW picked up this year), they can maintain advantages and exploit that constant pressure.
There are also 24 minutes per game during which your 2 lead scorers don't share the floor, and it's really useful then to always have an All-Star level guy in all lineups.
You and I are typically making the same points. I think in this case, there's two places we differ. One is that I believe fit matters a great deal and the defense and passing fit here is just 'ehh'. The second (which has come up before in our exchanges) is that while we both think wings are critical, I put some more weight on bigs and size than you do (or than benhogan does). I'm far from the group that thinks Embiid is the bestest, because most of us know it is not 1985, or even 2005, anymore. But I think most recent champs have had an above-average 5 and that's worth noting. That's not directly relevant here, but it is part of my roster building concern around theoretical Mitchell/Ant (as you proposed not getting Gobert and dealing KAT)
Who is the team that won a title with two primary ballhandlers who were middling passers, in your mind? That is where we differ perhaps in terms of fit and playabilty. Here's the last ten champions - which I think you'd agree is 'modern basketball' and I don't think it really fits the theory very well.
24 Celtics (Tatum for sure a better passer; White, as third guy also is)
23 Nuggets (Joker, obviously)
22 Warriors (Curry)
21 Bucks (GA, and probably also Middleton and Jrue...I guess one could try to argue this one?)
20 Lakers (LBJ)
19 Raptors (this is the closest---though Kawhi, Siakam, and FVV are all better passers than Ant or Mitchell, albeit sorta close)
18 Warriors (Curry, Durant)
17 Warriors (Curry, Durant)
16 Cavs (LBJ)
15 Warriors (Curry)
14 Warriors (Curry)
There's a plus passer in the top pair of ballhandlers for all of those teams. Often two. That is what I'd worry about with the admittedly fun and versatile Mitchell/Ant pairing. Maybe you can pull it off---those guys are super talented. But the concern I raised is pretty clearly supported by modern basketball history, too