Computer Build for Premiere Elements

You may not need that much RAM.  

I've been shooting and editing 4K source files since about 2014.  I've used "gamer" laptops with faster i7 CPUs, 16 GB of RAM and a couple different NVIDA GPUs.   A key for me is a SSD C:\ drive that has the editing program, project files, scratch disks, source media and output files on it.   Premiere Elements, Premiere Pro, Audition and AfferEffects all work fine.  My videos are rarely longer than 20 minutes.   Output rendering time varies, but averages around twice the length of the project. 

I only did a few test 4k files with my computer, and did not have any problems... your gtx 960 MAY be old enough that it is no longer updated by nvidia, but do be sure to use the STUDIO driver, not the gaming driver

What I have, with ZERO problems
Windows 11 Pro 64bit version 21H2
Premiere Elements 2021 upgraded to version 2021.4
Intel i9-10900k Motherboard ASUS Prime Z490 P
64Gig Ram and GTX 1650 MSI-GeForce-128-Bit-Graphics 4 Gig video ram
nvidia STUDIO driver version 511.09 (NOT the Gaming driver)
motherboard automatically turned integrated Intel video off when installed GTX
TEAMGROUP 512Gig SSD for Windows and programs and usual MS Office Documents files
500Gig SSD Temporary work files and output when creating new video files
1T SSD Video and sound files from camera and other sources