My neighbor has not talked to me in years because I called the system, very much like this one, that she had just bought for her son's birthday a P.O.S. to my son who then repeated that to her son who then repeated it to her. (the first thing that son did when he got a job was to come to me any say, "I've got $1,000, what can we do?") (he was able to upgrade the original GTX 970 to a GTX 1070 Ti without a second thought a few months ago)
Stay away fro the 1060 3 GB. That VRAM amount may very well become a problem.
OP, the one card that has not come up is the GTX 1050 Ti. This would be the safest bet for your system
as is. If you want more GPU power, you'll need to upgrade the PSU as well, which is not hard. (you should be able to find some Youtube videos to assist you)
Here's a nice PSU on sale:
Combine that with a:
GTX 1060 6 GB
GTX 1660
GTX 1660 Ti
RTX 2060
https://www.newegg.com/Product/Product.aspx?item=N82E16817151095
Of course, after all of that, your case has to be able to physically handle the size of the GPU and handle the additional thermal load.