Ok, so I am guessing you have a keyboard and mouse you can live with currently.
It's usually easiest when using PCPartPicker.com. Go to that site, and in the upper-right, there's an icon of a flag, with a country name next to it. You can click the down-arrow which will bring up a list of countries. Maybe pick a preferred country, and one or two others perhaps, and we can get to work on it.
At the moment, you have a 1080p monitor with 60Hz refresh rate. What are you considering getting as your monitor upgrade in the future?
My basic suggestion at the moment would be to put together a system that uses a Ryzen 3400G as your CPU. It comes with integrated graphics that are a little better than your existing GPU (slightly lesser than the GT 1030 GDDR5). Get a good PSU that can handle a powerful add-in video card later, but, do not actually get a new GPU yet. Wait until you have determined what monitor you're going to get, and have the money to get both the monitor and the video card. I would never suggest getting a GPU before a new monitor unless the new monitor is going to come pretty quickly after the GPU.
The idea is to get the GPU later, as the later you get a GPU, usually, you can get a better price/performance than if you buy significantly before you need it.