Benjamin Olson
Hero
Spell mastery: longstrider (cast hourly on him, sim, and mounts), Tasha's Mind Whip.
Signature spell: Hypnotic Pattern, Bestow Curse.
Prepared spell list on the day of the fight (for the wizard, on the day of the fight): longstrider, tasha's mind whip, feather fall, absorb elements, crown of madness, dispel magic, haste, dimension door, hypnotic pattern, resilient sphere, mental prison, otherwordly form, fireball, power word stun, freezing sphere, ravenous void, planeshift, teleport, dark star, demiplane, imprisonment, timestop, wish, chain lightning, time stop.
[plus Suggestion (racial) Animal friendship (racial)]
I believe you have 25 prepared spells listed (though I counted 6 times, and got 26 two of the times). Timestop is listed twice, and you don't need to prepare Hypnotic Pattern, as it is one of your 20th level signature spells. So by my count you are entitled to prep 2 more spells.