Gotta love having to defend my decisions when my party was fine with it and my DM was convinced, lol. Everyone there has enormous trust in each other, which is why it took very little time to convince the DM that my efforts were purely for in-character reasons and not to cheese the game.

It became pretty fluid, really, where I would just say to my DM "Simdaeron does the thing" (my guy's name was Daeron) and everyone would chuckle before a shiny new Simdaron would show up, based on the original Daeron, and immediately go to sleep or keep adventuring with the rest of the party. I even did the Wish+Simulacrum spam part with a private session (we each got one during our downtime to do random stuff) so the party wasn't even inconvenienced. Then, as soon as the small army of Simdaerons got me access to my second 9th level Mystic Arcanum, they never showed up again, with me only having one at a time.

For what it's worth, the "extra slot for Mystic Arcanum" was just having access to True Polymorph and Wish, but only being able to choose 1 per day to cast, so I didn't even break the game on that front. The only way I did was by getting at-will Distort Value which made my deception like 5% more effective (my Warlock was a genius, but also had 5 Wisdom, so he wasn't thinking about getting Burning Hands or something -- no, he wanted to get the ability to make items seem twice as valuable as they were).