Ok, thanks. Wasn't sure if this was an oversight or intentional. If it is not a bug, I will post it under the suggested improvements thread.

Selector Combinators should have the "any quality" option under "quality transfer" for both "direct selection" (for circuit contolled filters) and for the "target signal" (for reading items on a belt/chest). Screenshot 2025-08-22 215154.png

This way you would be able to set filters on inserters ...

Compact Celtic Knot with Narrow Tracks
Score: 55

Blueprint: LHD RHD Size: 38 x 38 Spacing: 2 tiles
LHD: Set 1: 56, Set 2: 42, Set 3: 66, Score: 55, RHD: Set 1: 56, Set 2: 42, Set 3: 66, Score: 55
Author: dinglebarry
LHD pic.jpg

Inspiration taken from gyro2death's Super Compact Celtic Knot ...

Compact Celtic Knot with Narrow Tracks
Score: 46

Blueprint: LHD RHD Size: 38 x 38 Spacing: 2 tiles
LHD: Set 1: 50, Set 2: 38, Set 3: 49, Score: 46, RHD: Set 1: 50, Set 2: 39, Set 3: 49, Score: 46,
Author: dinglebarry
LHD pic.jpg

Inspiration taken from gyro2death's Super Compact Celtic Knot ...