I assembled a PC today and when I started to test Minecraft I wanted to see how busy everything was and the GPU was 100% and 84 ° C. As a graphics card I have the Radeon RX590 FATBOY 8GB what can you do?
Activate Vsync.
You want 100% GPU utilization and 84 ° C are quite normal for the card
84 ° is no wonder at 100% load because the Fatboy variant was not the best decision…
Otherwise I'm amazed at the 100% load (since you started playing with shaders, 4K and high quality texture packs)