If you are on desktop and are willing to use a client side solution, my project can do some of this. I think it will be a while, till Itch presents a server side option for such things.
It is three things. A button for that obscure url thingy (It is an unpacked browser extension for chrome. The selected tag stays selected.) Buttons for the genres to filter them out (only by main genre. It is a tampermonkey script, so you need an extension that can run tampermonkey scripts).
And the last one is another tampermonkey script that does exactly what you want: ignore option for individual games or devs You hover your mouse over an item and press a key. The item or items of that dev go poof. Or get mirrored, turned grey or whatever - it is css.
I should update the description of the project a bit to emphasize the third tool, but I struggle how to screenshot what the third tool does. It is by far the most powerful and useful in my opinion.