Some problems with webview

Greetings. I have some problems with my app. First is the keyboard overlaps the text input field. I tried to fix this, but I could only by setting a fixed resolution in the application. But in this case, the interface of the site becomes too large, so it looks so-so. And with a fixed resolution, the text selection sliders slide up.
The second is that full-screen does not work in video players (YouTube too).

Please send the screenshot of your problem. Writing in text doesn’t give any sense.

The keyboard has to go somewhere. Either you make the rest of your app not use the area that the keyboard would occupy so it does not need to scale or scroll anything, or you suffer the indignity of having it cover some part of the application window.

How would you rather have it behave?

Well, I would prefer the first. For as far as I know, when you click on the input field, keyboard should automatically get under the field. And in this case there is no need to scroll, etc.

Then you make the area that is supposed to not be covered by the keyboard smaller so it would not be affected.