Buying more RAM won’t make any difference to your graphics capabilities. Thats all handled by your graphics card. The only improvements you might find over 32GB are slightly improved loading in times at the start of each flight and possibly less stuttering (if you experience any) The jury is out on whether there is much notable difference between 32 and 64GB of RAM. Some people claim to see not much difference going from 16 to 32GB. Depends on your set up I guess.
Considering the price of RAM at the moment I’m not sure the upgrade is worth the cost.