Xbox Server NA population is LOL

See the issue is. If you used a CR skip, you will be so weak at 333cr+ things. you will die fast, do no damage unless you know what you are doing.
Speedsters are hard to combat because their aggro is on other people most of the time. They teleport and aim at anyone in the radius.
You need to learn how to survive, block and learn the mechanics of the fight. When he sucks you in, roll away. When he stuns your team, breakout and lunge him. Deactivate his portals, run from his tornadoes.
You cannot just run content without a healer or tank (Idk what you ran with, you mention tank but idk the healer situation) The only advice i can give is to just learn. Sure you may get beaten around, but thats the point. You gear up, get your skill points, get your allies, artifacts, augments and you do better. MMORPGS are meant to be hard if you have no gear, the point is to grind and get better so you can do better things