MTG Salvation

New to the sub here, but I played a 4-color version of the deck this weekend at GPOKC. I went 7-2 day one with this list (https://www.mtggoldfish.com/deck/858562), but had worse luck day two – ending the tournament 9-6. Decided to drop the white in the sideboard for the GP, as I hated my sideboard containing a land and could not justify running a mainboard Godless Shrine. The Lingering Souls were also extremely underwhelming in testing leading up to the event. I managed to play against Grixis Shadow three times over the course of the tournament finishing up 2-1 versus the deck, and though it is a small sample size, I can say that the matchup is not as bad as it appears on paper. The only sideboard card that was pretty trash was Golgri Charm. I was expecting a lot more Supreme Verdict decks as well as Company decks, which is how it ended up in there. Have been considering a Snapcaster in its place. I would love any advice or suggestions to further improve this list.