I was referred to the following website when I asked support about where to buy RAM/memory for my AN515-52:https://www.crucial.com/usa/en/compatible-upgrade-for/Acer/nitro-5-an515-52
I then proceeded to buy this kit: Ballistix Sport LT 16GB Kit (2 x 8GB) DDR4-2666 SODIMM [BLS2K8G4S26BFSDK]https://www.crucial.com/usa/en/nitro-5-an515-52/CT12437476
Everything went smoothly until I installed the RAM and booted to Windows.
The RAM only runs at 2400MHz even though it's rated at 2666MHz. (timings are correct though)
The RAM that came with the machine ran at 2666MHz so I know it's capable of doing it.
This wouldn't have been a problem if I could've edited the speed myself in BIOS, but I can't, so here we are.