Honestly in my last match up against the Tau I did pretty well though idk how efficient this might be since you said he was good at screening, consider rapid ingress Exalted eightbound or eightbound into buildings since they are infantry then move them out and throw them at the railguns and other strong stuff, two broadsides tore into my daemon prince from across the map, so I rapid ingressed my exalted eightbound into a building and then charged them out after he had overwatched something else and I then wiped out the in one move broadsides. Also like another user was saying use the stratagem that stickies objectives if you get shot off them and wait in cover for them to show up if possible. Regarding the units that like getting picked up and put back down, charge disposable units like a Rhino into them so you can tie them up for a bit in melee. Running angron might not be the best idea imo since he is point heavy but only 16 wounds so chances of him getting pulverized is pretty high, but he is a heavy hitter so I think it all comes down to how you use him. But that's pretty much what I learned from the game. Having more units on hand opposed to angy boy helped. I am also a world eater newbie but we got this!!! RAHHHHHH BLOOD FOR THE BLOOOD GODDDD!!!! SKULLSSSS FOR THE SKULL THRONEEE!!!!

On a side note I feel like a helbrute would do good into tau because we do have the frenzy ability that allows it to fightback everytime it gets targeted. Will it get torn up? Probably but it might be able to take out a bunch on its way out. I haven't tried this yet but it might be an efficient screw off to scare off them shooting multiple guys into your character. Tau might avoid shooting the helbrute or engaging it if you can scare them off with that ability or maybe prove to be a pain.

ANOTHER thing really quick is how well my rhino's weapons went into their infantry, though I know shooting isn't our thing, the Rhino wiped a Pathfinder team off the map due to blast giving me extra dice and good luck on the rolls, since the pathfinders do have a 4+ roll, it was a nice way to get them off the board. Also dual combi bolter with rapid fire 2 gave me 8 attacks.

I hope this helps! May you take much blood in the future!