The only thing that an infinity really does for a mosaic sin is it helps you kill baal faster (or ubers).
I leveled up a a couple of mosaic sins and u might wanna give this a try:
an a1 merc with harmony, for vigor aura, and freezing arrow is really beneficial. Even tho you can teleport, or use dragon flight, that movement speed from the harmony is huge for your quality of life. And that freezing arrow is huge for getting your charges in cows (or anywhere that’s not cold immune).
Edit: but I used mancatcher when I did try an infinity. I prefer the harmony tho.
Okay thanks men , ive been always building trapsin! First time i will try mosaic and i want to run ubers and key's run