In the Instant Pot® inner pot, add 1 cup of water and insert the rack and a steamer. Put the potatoes and eggs on the rack.
Close and lock the Instant Pot® lid, making sure the steam release handle is turned to Sealing. Press Pressure Cook and set the time to 5 Minutes. After the 5 minutes are up, release the steam by pressing the button next to the handle. Remove the potatoes.
Mix the mayonnaise, Dijon mustard, celery, chives, and parsley in another bowl. Set aside.
Peel and chop the eggs.
Pour the vinegar over the potatoes. Add the eggs, bacon, Parmesan cheese, and pepper. Stir, add the prepped mayonnaise, and incorporate.