[2020] Serious question: what steps can I take if another player is harassing me and others online? Mcc-PC

I know the rules, not gonna rant. But today in matchmaking I got matched with a guy that repeatedly called others and me the N word with a hard R and then kept team killing us (or getting our shields down low enough to get one-shotted)

I couldn't find any option through Steam to report him, and tried on the Xbox companion app and couldn't even find his gamertag. Is there an in-game way to do this?

I know every game has its share of people who behave like this, 9/10 of my Halo experiences have been pretty wholesome lately, but this gave me some really bad 2007 flashbacks.

Really grateful to this community here just lovin the games, and I appreciate any help figuring out how to handle this. Thanks!