i googled this Visionplushdr ... and apparently its just some group that do HDR grading for movies.
I highly doubt what they do is better than original UHD releases.
1. studios have access to uncompressed full resolution video (luma and chroma channels)
these ppl likely only have access to UHD releases that have only half resolution chroma channel
2. studio grade colors on proffesional screens that have nearly full bt2020 colorspace coverage
i highly doubt these ppl have access to that as it cost tons of money
In short ... for best quality - stick with official releases on UHD ... unless you have enough connections, fame, and money to get DCI version
EDIT: 3. sometimes movie director gets involved in creating UHD titles to ensures it comes out as he/she intended it to be seen.
Claiming that someone can do that better is just funny