I think you tried the earlier versions of the full screen protector on the V20. Several months later after release, they came out with one that was 100% full adhesive, with the borders being glued down while the actual screen adheres like a real screen protector.
With super curved edges, I don't think any manufacture can do it. It's like the S8+ and Note 8, practically impossible and the only way is through wet install protectors.
Wet install protectors have gotten much better and they feel really smooth. I have a brand called Rinoskin for my Gear Fit 2 and the technology is amazing, looks and feels super smooth and scratches and dings automatically heal. If anyone wants to try the Rinoskin on the V30, let me know!