Should I upgrade to 32GB of RAM now, or wait for DDR5?

Upgrade to 32GB of DDR4 now. DDR5 is still expensive with modest real-world gains, and by the time it’s cheap and mainstream, you’ll want a new CPU and motherboard anyway. A good 32GB DDR4 kit costs $60-80 and makes a real difference for multitasking and heavy browser tabs today.