It looks okay on my device. (I’m visiting the site on mobile device)
For a fix, instead of using auto height for your logo on Mobile devices, set a definite value for height, keep width to auto and see if that fixes the problem.
I found 2 visual bugs though. Firstly, hamburger icon on menu button disappears when button is clicked and no cross icon is shown. This leaves a weird space on the left of Menu text.
Secondly, when there is an announcement bar on top. The menu bar moves downwards and covers some of the navigation links.
I suggest a small theme edit - the theme creator has used a srcset for that image, thinking that you’d upload something that needed to be resized. Resizing svgs and/or converting them to webp doesn’t make a lot of sense. The webp is actually bigger. (I suspect there’s also a typo, as the image src’s is set to 30w instead of 300w – and that’s probably where the blur is coming from.)
However, if you [right click] ⇨ [‘open image in new tab’]; You’ll notice it’s still blurry. Just a little less seemingly and probably due to the lack of anything else displaying.