No matter how much RAM is assigned, Minecraft still seems to use 2GB

No matter how much RAM is assigned, Minecraft still seems to use 2GB

What I expected to happen was...:
The amount of RAM Minecraft uses would increase

What actually happened was...:
Nothing

Steps to Reproduce:
1. In the Minecraft launcher, go to Installations > [Any installation] > Edit > More Options > JVM Arguments

2. Change the 2 in the first "-Xmx2G" to something higher

3. Open Minecraft using said installation

4. Go into a world and open the F3 screen

5. The second row on the right side will claim that Minecraft only has 2048MB total RAM