If you feel that maybe some discharge came out, but you are not sure whether it's really discharge or leftover wetness from instinja for example, or discharge that was there before you performed wudu, can you just ignore it? Or is it better to redo the wudu and prayer to be on the safe side?

All perfect praise be to Allah, The Lord of the Worlds. I testify that there is none worthy of worship except Allah, and that Muhammad is His slave and Messenger.

The mere doubt that some secretions were discharged does not nullify the ablution, and no ruling results from these doubts, especially if a person greatly suffers from doubts. Based on this, you are not obliged to repeat ablution, since certainty cannot be removed by doubt. You should simply ignore this feeling and pay no attention at all to the doubts.

Allah knows the best.