Correcting a turned video for proxying

Hey guys. I'm having a strange issue with DaVinci Resolve that I can't seem to recover from.

First off, I am using my Samsung Galaxy S10 for recording footage, but I did not catch that the orientation was in portrait until I finished recording and imported it into a project. The whole video is turned 90 degrees. Trying to proxy the video results in the same resolution at a larger file, and trying to reorient the video after proxying shows nothing changed in the viewport; I also can't choose the resolution of the proxy.

So, I tried to proxy the video after turning it by adjusting the rotation Clip Attribute, however it output a proxy video with the resolution still in portrait, but the "turned" landscape footage in the middle - in other words, a completely useless format that had massive black bars on the top and bottom!

I searched for a solution, and came up with using VLC to turn the video, then converting that video using the selected effect. It worked... sort of. Now the video is landscape, but also flipped horizontally in DaVinci Resolve. As of this writing, I'm attempting to proxy the video anyway, but I have no idea if it will work.

Is there a better, easier way to do this? I feel like I'm missing something obvious, but I don't know what it is.

EDIT: The VLC convert proxy turned out the same way. I feel like I should also mention that DR is reporting the video as 2160 x 3840, while everything else, including video converters, is reporting the video as 3840 x 2160. Yet, no matter what I play the video under, it is still sideways.

Also, in the video attributes, the orientation is automatically set at 90 degrees. However, setting it to 0 does nothing for the proxy - the proxy still turns out in the same portrait video format.

Yes, that's a bug, or at least, an irritating limitation. Even if set to original size, your proxy will display smaller and you'll need to zoom in for the viewer.
I'd suggest making your proxies after correcting the clip and rendering them as individual clips.

I finally fixed the issue. The fix?

Simply put the video back on the S10, use the Samsung Video Editor to rotate then save the video, transfer that back to my computer, replace the turned clip with the new S10 corrected one, and THEN proxy.

Problem solved! ...For now, at least.

It should be solved forever by holding the phone as intended for the final video