I'll take Arcanepotence. Isekai is most commonly known for their magic so being the omnipotent magician, it will be quite fitting

Subjective reality

Both are excellent answers!

Subjective reality can expand Isekai world magical powers .

If you believe in mind that magic have more capabilities than you experienced till that moment than in your hands magic will be not just magic but meta magic.

@LimittlesRealm Oh?

Subjective reality can weaken boundaries of imagination and reality and allow to create magic effects that work as indeterminacy for universe. You magic can gently transcend restrictions of world.

@LimittlesRealm Interesting. How would you use it?

Arcanepotence