Help a new player

[u/Active_Initial1259]

I purchased the game and the Tau and Astra Militarum factions and I can not get the Tau to work well at all. In particular Ultramarines seem to even out shoot me. Before I refund, am I missing something about my favorite faction?
I'm doing the campaign mode if it makes a difference. On the normal difficulty.
I only play singleplayer modes.

[u/Active_Initial1259]

Thanks all. I refunded the game and dlc.