Why not try Mailwasher?
There's 2 versions.
A freebie & the Pro, which I've been using for many years.
No rubbish spam gets onto your M/C.
Free >
https://www.mailwasher.net/
Pro >
https://www.firetrust.com/products/mailwasher-pro
(NB: I have no affiliation with either MWP or Firetrust. I just use the Pro version.)
ps. They do have a "Lifetime" option if needed.