Question Been a while since I did an upgrade need to make sure I'm not doing something stupid

Oct 21, 2020
My system build philosophy is buy the motherboard with the latest slots and then buy low end chips and components so in a few years I can upgrade the components and not have to change the board out. So i haven't been playing any games that push my system for a while until I went ahead and downloaded Baldur Gate III and it was obvious it was time to upgrade. Problem is it has been six! years since I purchased this system so I'm out of practice and not up on recent tech

First I will start with what I have:

Motherboard: ASUS Maximus IV Gen Z Socket 1155 2 PCie 2.0 x16
CPU: i3 2100 3.16Mhz
Memory: Mushkin PC3 12800 2 x 4GB
GPU: 2 nVidea GTS 450

So first the chip. I need a 2nd Generation Socket 1155 so I think this is the best I'm going to find. Is there any reason that will not work?

Next the memory. I have two empty slots So I was just going to shove 2 8GB sticks in there to raise it up to 24GB total Is there anything wrong with this?

It looks like the best cards I can put in a PCIe 16x slot is a GTX 500 series. Is it going to be worth the $400 to switch out the GTS 450s for GTX 500s?

Thanks for any help