Here is a shot taken at the wide angle end of my Panasonic FZ330. If you compare the out of camera jpg to the raw there is quite a difference. The raw is wider with lots of vignetting. I can crop the raw to match the jpeg which gets rid of most of the vignetting but then I lose pixels. The camera is probably upscaling. I was just curious to see what you experts could do with it
Emphasis in this edit is on the lens weirdness, rest is secondary.
I would personally crop out the wall that shows on the left and the shadows sticking in from the bottom (on 1/4 from the right), but this shows how much of the image can be “salvaged”.
Main problem here is that this camera and the accompanying lens are not supported. I choose the FZ300 body and the (Leica) FZ200 lens, which gives the same result as yours. I did add a touch of Distortion Correction and Vignette Correction. I also straightened the image by +1.83 degrees (which does take away just a bit of RAW real-estate).