I specifically use the Delock 62967 DisplayPort 1.2 to VGA Adapter. It uses a 270MHz Analogix ANX9847 DAC which is rated for 2560x1600@60Hz. It's been about 5 years since I got mine, so I haven't done any research as to whether there are better ones available today or not. I recall there were some really highly rated USB-C to VGA adapters, but my GPU didn't have USB-C output.

When I say that the DP to VGA is softer than my native VGA GPUs, it's only when doing a direct A/B comparison. There's slightly more blurriness to the text in the corners. Under normal use, browsing, gaming, videos, it's not noticeable.

Honorable mention goes to the Benfei DP to VGA cable. I bought a couple of these for a different application and they work just fine above 1080p as well, but I haven't properly compared them to the Delock or older native GPUs.