RAM Settings

I have a problem. I have 12 gigabytes of  RAM, i allocate 6 G, but it only uses about 26% of the RAM i gave it. These are the arguments: 

 

-Xmx6G -XX:+UnlockExperimentalVMOptions -XX:+UseG1GC -XX:G1NewSizePercent=35 -XX:G1ReservePercent=35 -XX:MaxGCPauseMillis=50 -XX:G1HeapRegionSize=32M

 

Problem is, i cannot change the 32M in the last line to a higer number because it gives a error that says: Error creating Java Virutal Machine. It only works when i set it to the default, 32M. Is there a way to make it use at LEAST 70% or more? (85% preferably). I may be wrong, but is it because 1.17 doesn't use JRE, instead it uses JDK. Does it affect it?