*December 4th 2023 edit: TEAM SERVERS ARE BACK UP, INCLUDING TEAM CREATION. No clue on how long for, likely not very long like last time*
EA have done a nice thing just in time for The Game Awards and have turned the skate.Feed servers back on meaning this and a few other achievements are obtainable again. Also, with the game being backwards compatible, every Xbox One/Series user counts as using the On Demand version of the game since the console doesn't install from the Disc of 360 games, meaning most of the player base can now join each other with no problems due to not having the disc patch (which also might have just been added as a free DLC for digital users to redeem now anyway, iirc it was the Skate Share pack that caused incompatibility but I am trying to think back 9 years).
Load up the game and open the pause menu and go to the Xbox Live tab. Scroll to skate.Profile and open it up. Once it loads you can alter your online profile and create and manage teams.
Either create a team or keep an eye out for one of the many Gaming Sessions that should pop up now that this game is completeable again. It shouldn't be too hard to get 5 other players either through here or Xbox's Looking For Group feature.
Once your 6 are ready, someone needs to launch a Team session by pressing Start > Online Challenge Map > Team Freeskate & pressing Host once the it times out finding an active one. Everyone else in the team can then do the same to join it. If you keep getting the error that keeps kicking someone as they load in, get them to restart the game or sign out & back in to EA Nation and it should go through eventually. The team server seems to be only running on a small amount of hosts, if not just a single host that someone at Black Box/Frostbyte has decided to run in secret until EA higher ups get wind & order it shut down again.