From my point of view, this is all relatively unstable and not really well thought out, far from being reliable. I have spent the last 2 weeks trying to convert my Crossbowser bookmark backend (https://codeberg.org/Offerel/SyncMarks-Webapp) into a functioning PWA. Very disappointing. Don't ask me how many nerves I've lost in the process. At least you can now use the WebApp as a PWA. The share_target also works if it was installed via Chrome or Samsung Internet. It also works offline. These functions are even retained if you subsequently uninstall Chrome/Samsung Internet. The WebApp then asks which browser wants to take over the functions. This also works with Chromite or Firefox. Strange but what the heck. At least you can now share any URLs with the backend. This also works offline, even if this is more of an Edge case for bookmarks.