Problem with Minecraft reported.
Problem with Minecraft reported.
Incorrect adjustments to the core engine. As noted by @Stahlmann98, anticipate no major overhaul due to the immense time required to reprogram Minecraft.
Didn't modify the memory allocation? Navigate to profiles, locate the desired profile (e.g., 1.16.1), explore further options, identify JVM arguments, and adjust them accordingly. For example, change -Xmx1G to something like -Xmx8G (8GB RAM). Your specs: 2600x, 16GB RAM, 3000MHz RAM, GTX1060. You're seeing around 6-800 FPS with unlimited FPS enabled.
This might also work for you, though I hit similar boundaries with Minecraft-like op. You're running 3700X with 16GB of 3600MHz RAM and a 1080Ti. If you haven't already, add OptiFine. Your cap is 16 chunks while maintaining 120Hz on your monitors.
Optifine is an excellent choice. For older versions such as 1.12 and below, consider Labymod or BadLion Client, which offer more flexibility in video settings.
What a puzzling term—"game" mode? I've never seen it on Windows. It's nice to know it can actually lower system performance.