I suggest creating a public list of known spam addresses. This list could be initially curated by Proton Mail and then maintained and continuously updated by the community (for example, via GitHub).

Additionally, it would be highly beneficial to add, in this section (https://account.proton.me/u/78/mail/filters#spam) within each user account’s spam filter settings, a feature that allows users to upload one or more precompiled lists of spam addresses (e.g., in .txt, .md, .csv, .json, or similar formats). This would enable users to manage their own personalized lists and import them all at once, rather than having to mark addresses individually.

Furthermore, there should also be an option to upload files containing lists of blocked addresses.

I consider this a high-level feature that should already be available in Proton Mail.