Antialiasing no longer works in Minecraft 1.16 and versions beyond
Since the Minecraft 1.16 snapshots when Mogang introduced a new rendering engine for minecraft Antialiasing no longer work with the game entirly. I have submitted a bug report to Mogang but their reply was "that's to do with your graphics card/drivers, not an Minecraft bug.".
My friend has an Nvidia card and it works fine, I'm not sure what the issue is.