nvidia is always 3 steps ahead than amd
Used GTX 1060
In all seriousness, why do you even need a better GPU than that?
I don't think you should upgrade to a "budget" GPU if you have that card. If you really want better GPU, save more money and buy 1080 TI (2k series not worth it IMO).
RTX 2080 is what you need as budget GPU.
If you are thinking mostly about playing games like CS:GO, FIFA, Fortnite, LOL than GTX1050 will be enough. You may try to get 1050 Ti but for those games u dont need nothing better, especially for CS:GO (CS = 80% CPU - 20% GPU)
Used GTX 760 or GTX 750Ti is enough for csgo also GT 1030 is good
Get a 1050 (ti) or get a rx 570, 560 is a little low i think. but if you are on a budget i suggest looking for used GPUs
rx570 / 1050ti. Buy the cheapest
Nvidia is just better in high end, 1070 and above
Medium and low end, Rx590>gtx 1060, Rx580><gtx 1060, RX 570>1050ti , and lower end aAmd is just better.
BUT if you are on the budget, look for used GTX 970, GTX 780TI