Oh geez, your comment reminds me of like 8 years ago. You've really been out of the loop haven't ya? Yeah, what you say used to be true, but that's not what I'm talking about.

All splitters today can split items off. You can just click on a modern splitter and say "Left side Iron ore", and all iron-ore leaves the left side of the splitter, and all other items go out the right side. This operates at full speed, no glitches.

> so I guess it can be set up to filter as many types as you like?

So use a splitter per item, and then merge the belts back together later.

If you have 5 items to sort, create 5 filters, and then run the belts to route them where those 5 items need to go.

For "Meta" builds, the key requirement isn't size. Its throughput. When you have 5 filters inserters, you barely will have ~10 items/second throughput (and that will glitch out depending on how successful your inserters are at picking up items, corners can pose issues for example)

When you have 5 filter-splitters (on 5 different items), you easily prove that every decision point operates at the full 15/30/45 items/second (yellow/red/blue belts respectively).