It really depends on what resolution and your budget. If your resolution is 1080p and your budget is limited, then I recommend sticking with a 1080p resolution, as that will allow you to upgrade reasonably without having to resort to "low" and "medium" graphics options.
If your resolution is 1440p or higher, then you will need to make concessions if your budget is limited.
I'm not going to recommend specific components but rather things to consider that will hopefully help you come to a decision or at least help narrow down your choices:
Resolution - honestly 1080p is fine if you have a limited budget. Don't get pressured into increasing your resolution if you don't have the budget, as increasing the resolution will also cause your GPU requirements to increase (unless you are fine resorting to "low" or "medium" graphics settings).
Storage - again, if your budget is limited, SATA SSD's are fine. You do not NEED an NVME drive, especially considering there are only a handful of games that support Direct Storage. That said, it would be beneficial to purchase a motherboard that supports an available NVME slot for future proofing your upgrade. Which leads us to...
Motherboard - You can easily get lost down a rabbit hole when it comes to motherboard specs (chipset, I/O, # of SSD slots, PCIe version, etc). If you are on a budget, might as well stay within PCIe gen 4 for SSD and GPU speed. However, there are some motherboards that may offer at least one of the two that won't break your budget, but you'll need to decide which one you want, PCIe gen 5 for SSD speeds or PCIe gen 5 for the latest graphics cards. If I had to choose between the two, I would go with gen 5 for the GPU slot.
CPU - If your monitor supports higher than 60hz, it will be worth getting a CPU powerful enough to be able to deliver frames that your monitor supports. But if your budget is limited, sicking to a CPU that will support 60 FPS is what you'll want to focus on.
GPU - If you are sticking with a 1080p resolution due to budget limitations, you can't go wrong with an AMD card. While Nvidia cards are great (I own an RTX 4080), you can easily exceed your budget with them. If you are trying to stick to a modest budget, I would not consider fancy effects, such as ray-tracing, to be part of your goal, as while they are nice, they are currently a luxury feature and not a required one. The other features such as DLSS, while great, are available in other flavors such as XESS and FSR. This mindset will allow you to focus your GPU purchase decision on performance rather than luxury features.
I hope this info helps you get a better idea of what kind of upgrade you are looking at. Best of luck and enjoy the fun of upgrading your rig! Share some pics of what you have under the hood when its all set up!
Power Supply - There are sites that have calculators on how much wattage you'll need. Essentially you'll want to have a couple hundred extra watts above over your estimated total wattage usage.
