Multiplexing potentiometers

some different uses and space problems

Is not an adequate description. Are you serious about getting help?
If so a full explanation is required rather than something vague.

it can't detect itself which input I'm activating as the encoder does.

If you have a pot on the input then there is no way a MC14532B or an SN74HC148N can detect any activation of that pot. These are digital input devices.

Draw a schematic of what you are proposing and we can see if it is feasible.