I suggest improving Proton Mail's blocking feature by allowing users to block emails based on top-level domains (TLDs).

Many people fall victim to spam despite themselves. Offering them the ability to block TLDs they are certain they will never communicate with (e.g., *.ru, *.xyz, etc.) can help restore a cleaner inbox for the user, while also avoiding unnecessary storage — both for the user and for Proton.

Since this feature is powerful and could inadvertently block legitimate emails, it should be accompanied by clear and precise explanations to warn and educate the user.