So first, Guide posted on mondrith is outdated I think.

Filtered inventory cable connector doesnt exist anymore, instead it says to use the inventory configurator to filter it.

so I set up an scenario simmilar to what is shown on Guide video on minute 4:45 https://www.youtube.com/watch?v=nW5ElcWiC3c.

For instance if I remove the filter in the midlle inventyory cable connector, is still doesnt bring the remaining items from the source chest.

Using materials (I,E wood blocks) instead of item filters seems to make the connectors ignore them and pass all the items

Yeah, the guide no longer works for 1.21, specially since a lot of functions were added to the Inventory configurator, which I have no idea how to use it. 1.19/1.20.1 versions were way more simple and straightforward to understand and use.