5700XT is faster than the 2070 from 10 to 30% in games with latest drivers. If you mean 2070S, the reference is in par to the 2070S.
As for which one, XFX 5700XT Thicc III goes for £351 these days. Has the best cooler of them all except the Nitro. But the latter is 10% more expensive.
Have a look one of the most recent reviews using latest drivers on the reference model (the one that is hot and slower compared to AIB ones) go through all the games there.
https://www.guru3d.com/articles_pages/powercolor_radeon_rx_5600_xt_red_dragon_review,13.html
(the review is for the 5600XT but latest drivers are used on all cards)