Theres a few problems
From a gameplay perspective, muskets and rifled muskets are pretty boring. You occasionally see these roblox or shit tier games where players like to larp and line up in a firing line and maybe volley fire but 99% of the time players will play like deathmatch and run around wildly with no organization and be fine, which ruins any sort of historical accuracy and the vibe in general.
Theres also the problem of artillery and the rest of the shit being a boring job. How can you make that balanced but also impactful?
I could maybe see it working better if each player had command of a bunch of AI soldiers and directed them around, and tons of them could die and be reinforced like a horde.