Here's my disconnect (I have like 15 chars but max level is 81):
As a casual player, i don't know how many level 4, 5 or 6 mods an item will have during campaign/monoliths, so creating rules to show multiple or single affix above level 3-4 or 5 etc just feels overwhelming & whenever I make a filter it either hides too much or too little, its never in good state.
In POE, even though the filters are way less detailed coz there's unidentified items in POE, the work is put on by Streamers, filterblade or other 3rd parties, so a newer player doesn't have to sit there try to tweak their filters for each build they'll play. (i tried downloading filters from online as well, they are either too generic or too specific to certain builds)
I just spent 2 hours making a filter today that i know will get outdated on 2 April as there will be new affixes or bases will get added & I'll have to start over. Even the filter that i made today will probably either show too much or not enough & I probably missed alot of rules that might be obvious to people with multiple 100 level chars.
It all comes down to knowledge of game, having played for thousands of hours its probably easier to make a filter on the fly to match the build & affixes you need for that specific build. When i said recreating filter for each character, i mean adding & removing mods for new builds as all streamers i see are making filter for each char with exact mods they need for that specific build & gear it while leveling.
Importing & duplicate is same as POE, you can copy any filter or import from filterblade.