Thanks, I think you're right.The prices on DDR4 2400 to 3200 modules are all nearly the same at around $37, so just pick the cheapest with the fastest speed and best timings. The worst that will happen is it won't work and you will have to send it back or buy a second one. The only other practical upgrade would be a GTX 1070/1660ti/RTX 2060 as they are 100-110% faster than your GTX 960. Upgrading your CPU is not even really an option, because used and new prices on an i7-6700 or 7700 are still more than a new Ryzen 7 2700 or new Ryzen 5 3600. You are probably better off just saving to build a whole new computer if you want to upgrade the CPU.
I'll see what to do