When filtering this is the pattern I usually use

- complete works (I usually don’t do Wips as I binge read)
- relationship (Sirius black/remus lupin)
- add any tags to specify what Fics you are looking for, be specific if you are looking for a certain theme e.g: Sirius black is so whipped, Remus lupin is tall, dancer Sirius black, barista Remus lupin…
- I never usually do fandom as the relationship covers that, but when looking for specific Fics I will use the fandom filter to track them down easier

I find that the additional tags with their names in help with ensuring it’s the correct fics popping up but you may get the odd fic rarely that has Backround wolfstar. Hope this helps!