If "cards' names are practically meaningless without a score sheet", why determine suitability of cards by name? Nevertheless, I have a Radeon Pro Vega 56 8176 MB, which appears to exceed (by name) the Radeon HD 6570 you state as the current minimum; yet I still get the same error message.
Certainly the newer cards will meet or exceed requirements for the graphic needs of SimCity. The error message you're getting is probably just pointing to an issue with the game's interaction with your graphics settings or card, if you're lucky - sort of a default for graphic issues when it has nothing specific from which to draw.
A few things to keep in mind with SimCity - remember, this is a legacy game, programmed in 2013 with no updates since 2015. It does not play well with dual monitors or 4k monitors. Lower your resolution settings, and disable any dual monitor capabilities while playing SimCity. Is this on Mac OS? Make sure you upgrade to Mojave; the last few Mac updates broke SimCity for Mac users. There was a problem with Radeon drivers a year or two ago, so make sure your drivers are updated to the newest available. Double-check that SimCity.exe and Origin.exe are both added to your firewall and anti-virus exception lists.
You can also try to repair the game - in Origin, right-click the SimCity icon and choose "Repair".
If none of these general tips help, reply back with more info - what OS (Mac version, Windows 8/10?), can you click through the error and still play the game? Have you successfully played SimCity before?
