the itch.io dev tos doesn't require a dev to provide anything, it also allows a dev to delete purchased games. so reporting a dev will do no good. having the product flagged as owned and in your library (even if there isn't actually a download) is still itch's responsibility though.
and "tossed in the trash" is completely accurate,
it's not simply the nice banner saying you bought it, which also helps prevent accidental rebuying,
the key thing is leafo didn't hide the games, he removed them. yes there is a bundle page where theoretically you could click download at some point in the future if the store page still exist but it is not a true tied to your account DL link. so if a dev deletes a store page which is very common then you will never be able to claim the game. this is very important because only a handful of bad devs will delete the actual download once you've purchased, just the store page. and if it is banner up top claimed then even if the store page is deleted you can get a support email that will take you to the download, but the bundle page is based on the store pages, no store page, no download, even if a download exist for that game. this is why it is important for the product to actually be in your library as opposed to having the itch.io equivalent of an unclaimed steam key
as far as searching for something in your library it is easiest to search the store then use the owned banner at top, or use a 3rd party game library tracker like isthereanydeal.
https://itch.io/t/1001232/developer-red-flags-game-red-flags