Fury X vs 2060 FEI compared the cards. The 2060 would only be a 10ish% improvement over the Fury X, and that difference may be due to a newer platform for benchmarking than an actual performance difference. The 2070 is about a 30% improvement, and it's possible to get a custom block for that 2070 on eBay. But... I already had the Fury X for a couple years and that's not worth spending near $1000 on a 2070 with a custom block. The 1660 Super would be a downgrade.
Thanks for digging into it for me.
Heck, if cooling is good enough, you could possibly flash it into an rx5700xt.PowerColor has launched the RX 5700 in the ITX form factor.
https://www.tomshardware.com/news/powercolor-launches-radeon-rx-5700-in-mini-itx-form-factor
The RX 5700 is for sure faster than the Fury X.