How about allowing us to report spam and the mail client sorts it to the trash automatically?
I’m not sure there are accepted standards to allow reporting of spam to be handled in expected ways.
On each mail host you have configured, in the settings for it, selecting Folders, you can specify a spam folder for that host. When reading messages, from the … menu top right, selecting spam moves that message to the specified folder.
On thunder bird it did it for you, and would automatically delete it
Thunderbird can move a message marked as spam to a specified folder, and yes, delete it after a specified time period. Thunderbird also has some Bayesian filters to detect and score messages, although I’d trust server-side detection these days.
Doesn’t your email host have a setting to purge the junk/bulk folder after a period of time?