How to avoid quality degradation when resizing and converting to webp?

Question

Search Engine Optimization

I have a system where users upload their photos. When loaded, they are cut into three extensions and saved. There was an idea to pinch them in webp, because. Search engines love them, but when resized to an extension (270x270) and compressed into webp, the quality becomes disgustingly blurry on some pictures, and some are compressed with little or no change in quality. But the task is to ensure that the site does not have pictures with poor quality.
So far I have come to the conclusion that it makes no sense to convert to wepb when resizing, since the difference in weight is ~ 20-30Kb, and the quality is much worse.

Tried to convert via cwebp.
Via php Intervention Image (GD)
Via a third party site.
Everywhere exhibited quality 100%. But the result was almost the same.

If you had such a case, how did you decide?

Answer 1

Or maybe try to convert first, and then cut?

Answer 2

I had a similar situation, on some deshman monitor it seemed that the image was soapy, when I looked at the retina it was of amazing clarity. Apparently the renderers were different, I did not understand. Try watching on a different monitor, browser, etc.