What was shown in the first post screen shot was NOT about the AMD graphics card, but separate information about the USB controllers, which are totally different.
It is not that RealFlight as stopped supporting AMD, but that AMD stopped supporting the older graphics software that RealFlight is dependent on. See the posts near the top about this in the News and Announcements section. Almost all of the issues involve not being able to fully start and run the software, not slowness in the controller response. The fix involves using very new graphics drivers from Raedon. Unknown to me if the card mentioned in the first post can be updated with those drivers or not...but it doesn't sound from the symptoms like is needed to be done, and doing it may make things worse, if not approved by Raedon for the card. Reserve trying that as a very last thing, and make sure you know how to get back to what you currently have before trying.
The "run as administrator" tip is always good, and safe.
To help, we need more information:
Version of Windows.
Is this version of RF installed from discs, or downloaded from Steam?
What controller - if a RealFlight interlink, what kind (from the label on the front). If a "real" radio, what kind?
Are you running Antivirus or Malware protection software - if so, what brand and version? Have you tried temporarily disabling it, to see if the connection speeds up?
Have you tried different USB ports on the computer? Some may be running different versions of USB than others.
Have you tried a new USB cable, if that is possible?
Can you get/borrow a powered USB hub and give that a try? Some systems have trouble supplying enough power to the controller over their normal connectors.
Are you SURE the video is being sent via the "good" graphics card? Some PC's (my newer laptop, for example) was only advertised as having Nvidia graphics...but actually came with that AND built in Intel graphics processing on the motherboard. Out of the box, it only used the very poor Intel. I had to disable that, to ensure I was using the high performance card. Yours might have something similar - and if the system is really struggling with trying to process the graphics, that could lead to slowness for other things - like the controllers.