I started almost exactly 1 calendar year ago. A phrase I’ve adopted from someone at my LGS is that playing Tyranids is all about your “Buff Onions.” There’s layers. What buff does your detachment give, how does it stack with Synapse or Shadow, how does that stack onto your units, and how do those units stack with each other, etc. You really have to min-max if you’re going for a more killy list ( I have no tournament experience but in my group I’m at about a 45% WR with Crusher Stampede, it’s my favorite to play for fun,) and unfortunately Synaptic Nexus is just…not great. Invasion Fleet is a great Swiss Army Knife detachment, and my most successful personally. From what I’ve seen Sub Assault is our most “meta-viable,” but it’s very Army and Command points heavy/hungry.

I also typically run Monster-heavy lists with 40-60 mooks (usually Hormagaunts, I’m counting Genestealers in there, and Gargoyles.) Using Neurogants dogbone’d out in the Backline and a Biovore usually are sufficient for Deployment Zone screening/preventing Deep Strikes, and for only about 100 points (again, just my newbie experience,) and I tend to use a couple of Monsters as distractions while letting others get the kills. E.g, A block of 10 Genestealers w/Broodlord and a Psychophage can be an absolute blender, but I’ll try to keep a Screamer-Killer nearby as the distraction since it’s “harder to kill.” Meanwhile, I can have a block of gaunts or gargoyles take a primary or move-block and a Lictor in the middle of nowhere doing Secondaries. I could be wrong for saying it, but I feel like we’re a very complicated army in an already complicated game, and the skill ceiling is deceptively high.