The conversion that keeps everything
PNG is lossless and has a full alpha channel, so it can hold anything a WebP carries except animation. Transparency survives exactly, and no further generation loss is introduced — whatever the WebP had, the PNG keeps.
Expect the file to get larger, often substantially. WebP was designed to beat both PNG and JPEG on size, so trading it for PNG gives up that advantage by definition. That is the price of a format older software can open and of pixel-exact editing.
Choosing between PNG and JPG here
Pick PNG when the image has transparency, contains text or sharp edges, or is headed for further editing. Pick JPG when it is a photograph and size matters more than the last few percent of fidelity. If the result is bigger than you want, compressing it will bring it down without changing format again.