Any advice is appreciated
My group and I play twice a week at 2000pt and I'm sitting solidly at a 15% win rate with my Sisters. Feels like I've tried nearly every build I can support, every strategy and nearly every model and I cannot punch through the stuff they're bringing. I've been finding a lot of games I am either being overwhelmed by hordes or specialized units screening my objectives and ingress points or just plain being vaporized by some cannon I can't hope to do damage to. I'm not against losing models to trades, and I'm trying my best to make sure I'm actually able to complete objectives, but playing is quickly becoming no fun. Any ideas on lists that actually work?
Players at my table are "Oops all tanks" Guard (Hellhounds, Rogals and Baneblade), "Oops all Mechs" Tau (Riptides, Stormsurges and Ghostkeels), "Elf Speedball" Aldari (just elf shenanigans), Necrons, and "Me and my Million Friends" Tyranids (so many 'gaunts).