Yes I have used it before. I have invested in 3 funds via UpMarket, each were filled with a warehoused portfolio and when I entered I was already at a 1.3X MOIC.

I also invested in 3 funds via UpMarket. All of them had warehoused deals, ranging from allowing me to enter at a 1.4-1.7X MOIC upon entry. Are they willing to let you raise capital from LPs on their platform?