https://2e.aonprd.com/Feats.aspx?ID=6064
From reading this, it doesn’t look like it would affect your other spells at all:
Your mystery grants you additional magic. You have an extra spell slot of your highest rank, which you can use only to cast one of your mystery's granted spells, heightened to this rank.
Special If you have the divine access class feature or Mysterious Repertoire feat, you can cast spells that you learned from those abilities using the additional spell slot from Gifted Power.