I get round this by creating a rule such that any domain ending in .ru is filtered to junk. There is no circumstance where I’ll need an email ending in .ru. I do the same with some company domains, e.g., @xyz.com. I’ve been doing this for about two years.
This doesn’t end all spam of course but I seldom get more than 3-5 spam emails in my inbox a week. But, if I go to my spam/junk folders I have hundreds!
I admit I get a certain satisfaction in seeing all of that spam filtered away. 
I’ll add, based on this thread, that I create all my rules server side so they function across devices.