Yes, 1.18 doubled the chunk size. This is why I put out a PSA in Discord, if you do not follow the discord anoucements, please read my updated fix lag guide on how to fix your clients for 1.18+ with doubled chunk sizes, you are receing not only double the data PER CHUNK but also you are now geting 7 render distance, where as before it was 4! The sheer amount of extra data coming your end to load the world has massivly expanded.

Make sure to also read the networking section to test and improve your network connetion

How to fix Minecraft lag