Alt and Title attributes are present in the Media Library. But absent in the source code. I use Classic. And Shortpixel Image Optimizer for compression and usage of .webp.
At the moment .webp is organized by adding <picture> tag to the source code. But using .htaccess result in general is the same (in this case alt tag itself is present in the code, but with an empty value).
Important that alt is absent for images that were added via Image Gutenberg Block. For other images, like featured image, alt exists. Title is present only for .svg logo.
Yes. I have tried to deactivate Shortpixel. This plugin is not guilty.
Native Gutenberg Image Block is. To have alt and title in Media Library is not enough anymore. You need to add them additionally to block settings. Very useful update from WordPress developers :))