I don't know what it did, or if it did anything at all, but I set Minecraft to be included in my VPN's tunneling and it started working now.
Yes, the issue still occurs after 1.18.2. As of today, the problem is still present.
I too have horrid lag on realms. My friends and I tested by flying to an area we had not built in and firing an arrow. The arrow travelled slow and staggered. The lag is from the server, not you.
Responding to [Mojang] Mega_Spud, Issue is still valid and presently occurring.
I also have more information. I launched the game to see if anything changed, and I looked at the GPU core clock this time which I did not do before. The clock was around 600Mhz. Very low for my overclocked 3060 which usually boosts up to 2070Mhz . No other games that I'm currently playing exhibit this behavior either (Team Fortress 2, Half Life 2, Doom Eternal, Titanfall 2, Rocket League, Elden Ring, and Grounded), they are all boosting to 2070Mhz as normal. In Minecraft, the memory clock is also not maxing out. The memory clock in MC is about 5000MHz, whearas other games are pinned to the max of 7776MHz. This is just a feeling, but I think the problem may be a driver issue on nVidia's side.