My PHP Version are all up to date.. or what do you mean?
Just that ^
It was not stated (so unclear) from your opening post, which PHP version / release you were using and the image of the PHP ImageMagick Extension release that you had shown in your opening post, was out of date. You've changed the image of the PHP ImageMagick Extension release in your 2nd post, so either the 1st image was the wrong one (an old image) or you've updated things since your opening post.
That ^ doesn't matter in the end as you now appear to have what was questioned anyway, yet, still appear
not to have WEBP support in the PHP ImageMagick Extension that you are currently using.
WEBP support within the PHP ImageMagick Extension is available
by default, in both of our PHP 7.4.* and PHP 8.0.* releases (via Plesk) on Ubuntu 20.04.3 LTS
You are on Ubuntu 20.04, at least according to your signature, that is a difference, i think.
Haven't checked the Ubuntu release pages to verify that ^ (maybe you have?) but with hindsight, yes you're probably right there.
This Plesk support comment seems to confirm that thought too:
Just in case... You've already tried this:
Install ImageMagick with WEBP on Ubuntu 18.04 but it didn't work for you. Is that right?
If so and you've looked at / tried everything else, you might need to move from Ubuntu 18.04 to Ubuntu 20.04 OS
if this functionality is vital for you.