Lurrus as companion (Duel Commander)

I love deckbuilding, and none of my decks have been as difficult to build as this one. I was inspired by the Athreos/Lurrus combo, and my first attempts at a deck with this combo were absolutely abysmal. I realized that being able to control and compete in a 4 player match with Athreos/ Lurrus was swimming upstream. The deck has been pivoted to Duel Commander, is tuned for 1v1, and this latest build has been ripping apart EDH decks with ease. It's fun to play, consistent, very often overbearing and overwhelming quickly. There's 3 more lands amongst the cards, for a total of 33, since all your permanents costs 2 or less you can operate without many.

It says the deck is illegal because it has 101 cards, but Lurrus as a companion is "outside of the game" and therefore doesn't count towards the 100. Can anyone confirm this for me? Otherwise, take out a plains, bringing you to 32 total lands

I'd love feedback or suggestions. Or if anyone wants to play commander via video, I'm organizing some games so hit me up if you're interested!

9/16/2021 A couple improvements today, increased the size of the sideboard, which is for, by the way, 4 player games.

11/9/2021 Forget the sideboard, this is a 1v1 Duel Commander Deck. Added some small pieces, lands are down to 31 and you might be able to play with even less, with the 1.77 CMC avg right now it is lightning fast, with enough removal to general smother and win with small pecks. Fun stuff