PC upgrade with a $777?

Hello! I've had this PC setup for about 6 years (https://pcpartpicker.com/user/Diamondgigas/saved/#view=L7dQf7). Its served me very well, I've only upgraded the RAM from 2x8GB to 2x16GB. I've recently come into a voucher of SGD$777 (about USD$600) and I was thinking of allocating that to some kind of upgrade. I'm a 3D animator and work in Blender and Maya often, sometimes I notice my computer slow when I have too many rigs in one scene, or maybe I have too many tabs open while I'm working (more than 15). Would that be a CPU issue? I also like playing games like Baldur's Gate but usually have to play on low graphics to keep the game running smoothly. I know $777 probably isnt too much, and I don't mind going over that slightly, I could afford to fork in an extra $100 if the upgrade is worthwhile. Anyone have any recommendations?