You need to be a real Rick Astley fan to independently, industriously and, most importantly, selflessly upscale his “Never Gonna Give You Up” in 4K. This version of the most famous song of a pop star of the late 80s appeared on YouTube in late January and was only noticed recently.
User Revideo described in some detail the technologies he used. To increase the picture resolution, the software based on the artificial intelligence Topaz Video Enhance was used, and to convert up to 60 frames per second – RIFE (Flowframes).
The amount of time it took to process the source material (in those years, most likely, it was filmed on Betacam), one can only guess. However, this seriously depends on the power of the workstation used.
But as noted in the comments – Rickrolling will never be the same again.