You could add a very basic and necessary feature such as allowing the user to create FILTERS with VARIOUS options for deletion.
Allow me to set up filters WITH the ability choose the actions such as "delete with notification" "move to spam" "delete without notification" "move to ----- box" etc. Filters aren't enough, there has to be options for what to do with the filters.
Could this be a duplicate of https://protonmail.uservoice.com/forums/284483-feedback/suggestions/7253358-user-controlled-email-filtering ? You could reallocate your vote to that idea so it gets more visibility and comment how you want the feature to be implemented.