"Webmail" filter rules are actually quite flexible. However, a major downside is that all conditions are "AND" with no "OR" option, so all conditions must be met. This requires a separate rule for each sender when email conditions from different senders don't have a common identifying factor.
The approach I suggested above only has one rule for the other email to File into Spam, File Into Trash or Discard. (All unwanted email would have the same disposition). But, you could "Discard" known spam senders and have a mix of include and exclude along with the final File into Spam/Trash rule for all others.
For more information about using Webmail Filter Rules, see this thread. You may find that Webmail filter rules can filter email senders sufficiently well that you could change from primarily allowing wanted email to eliminating unwanted email. For example, you could send all email that contains newsletter@ in the address to Spam. You could "Discard" all email containing .co.uk in the address if you never want to see anything from those domains.