Iirc the artillery dug into the muddy ground and ended up mostly over shooting the union lines. But the other reality they were dealing with was the advent of industrial warfare. As you point out rifles were suddenly as easy to use as smoothbores, making infantry a lot more accurate and giving them a lot more range. The Civil War sits at the very start of a period of very bad times for infantry assaults, that wouldn’t be solved until tanks were invented in World War 1. Even the generals of World War 1 who grew up watching this problem become worse over their career, could not figure out a good way to solve this problem with solely infantry and artillery. I don’t think Lee could be expected to come up with an answer that generals with 50 more years of experience in industrial warfare were unable to find.
Iirc the artillery dug into the muddy ground and ended up mostly over shooting the union lines. But the other reality they were dealing with was the advent of industrial warfare. As you point out rifles were suddenly as easy to use as smoothbores, making infantry a lot more accurate and giving them a lot more range. The Civil War sits at the very start of a period of very bad times for infantry assaults, that wouldn’t be solved until tanks were invented in World War 1. Even the generals of World War 1 who grew up watching this problem become worse over their career, could not figure out a good way to solve this problem with solely infantry and artillery. I don’t think Lee could be expected to come up with an answer that generals with 50 more years of experience in industrial warfare were unable to find.