16GB RAM won't speed up Lightroom exports much.

Not really.

Export in Lightroom is almost entirely CPU-bound. Your Ryzen 5 3600 is decent, but that’s what determines how fast it bakes out the final file. RAM matters for how many raw files you can preview without stuttering, and whether you can stack a dozen layers in Photoshop without swapping to disk. But during export, the CPU is the bottleneck, not the amount of RAM past a minimum threshold.

8GB is borderline painful for Lightroom overall—you’re probably seeing slowdowns while browsing or applying edits. That’s where the RAM upgrade helps. But if you’re timing exports, going from 8 to 16GB might shave off a few seconds at best, mostly because your system stops hitting the page file. It’s not the magic bullet.

Get the RAM anyway—Lightroom on 8GB is miserable. But if export speed is your main complaint, the upgrade you really need is a faster CPU.