This barrel weight talk makes me think back to how they were handled in DOS2. They were actually extremely heavy in DOS2, to the point where most characters could only carry one maximum. Strength based characters could easily carry more.
Which is why I raised my eyebrow when I realized my BG3 characters could carry like 4 at a time, when my preferred party (DEX archer Bard/Shadowheart/Gale/Wyll) is generally lacking in strength to begin with. 10 weight is COMPLETELY absurd. (No, I will never include Lae'zel in my party.)
I found that in DOS2 it'd eventually spiral to being able to have multiple, also I had Fane ALWAYS carry around a barrel of poison for reasons. 5e Strength is more limited so once you are at 20 Strength, thats it, meaning that Barrelmancy would have less of a chance to spiral out of control, even with Casters who can produce floating disks or pocket spaces it'd still be limited.