i think even an rx 570 will still get bottlenecked by the cpu, i just recently upgrade my cpu from a pentium g2030 and upgrade my gpu to a 1050TI and wow most games are even unable to start cause of the cpu.
i would suggest an rx 560 if you aren't considering upgrading the cpu,
BUT
if you want to upgrade your cpu (and mother board + ram pressumably), yeah i would agree with rx 570 to upgrade